fixed version number

lyngweb: better syntax highlighting and code editor

.github/workflows/gradle.yml

@@ -1,54 +0,0 @@
-# This workflow uses actions that are not certified by GitHub.
-# They are provided by a third-party and are governed by
-# separate terms of service, privacy policy, and support
-# documentation.
-# This workflow will build a Java project with Gradle and cache/restore any dependencies to improve the workflow execution time
-# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-java-with-gradle
-
-name: Java CI with Gradle
-
-on:
-  push:
-    branches: [ "main" ]
-  pull_request:
-    branches: [ "main" ]
-  workflow_call:
-
-permissions:
-  contents: read
-
-jobs:
-  build:
-    strategy:
-      matrix:
-        include:
-          - target: iosSimulatorArm64Test
-            os: macos-latest
-          - target: jvmTest
-            os: ubuntu-latest
-          - target: linuxX64Test
-            os: ubuntu-latest
-          - target: testDebugUnitTest
-            os: ubuntu-latest
-          - target: testReleaseUnitTest
-            os: ubuntu-latest
-    runs-on: ${{ matrix.os }}
-
-    steps:
-    - uses: actions/checkout@v3
-    - name: Validate Gradle Wrapper
-      uses: gradle/actions/wrapper-validation@v3
-    - uses: actions/cache@v3
-      with:
-        path: |
-          ~/.konan
-        key: ${{ runner.os }}-${{ hashFiles('**/.lock') }}
-    - name: Set up JDK 17
-      uses: actions/setup-java@v3
-      with:
-        java-version: '17'
-        distribution: 'temurin'
-    - name: Build with Gradle
-      uses: gradle/gradle-build-action@ce999babab2de1c4b649dc15f0ee67e6246c994f
-      with:
-        arguments: ${{ matrix.target }}

.github/workflows/publish.yml

@@ -1,25 +0,0 @@
-name: Publish
-on:
-  release:
-    types: [released, prereleased]
-jobs:
-  publish:
-    name: Release build and publish
-    runs-on: macOS-latest
-    steps:
-      - name: Check out code
-        uses: actions/checkout@v4
-      - name: Set up JDK 21
-        uses: actions/setup-java@v4
-        with:
-          distribution: 'zulu'
-          java-version: 21
-      - name: Publish to MavenCentral
-        run: ./gradlew publishToMavenCentral --no-configuration-cache
-        env:
-          ORG_GRADLE_PROJECT_mavenCentralUsername: ${{ secrets.MAVEN_CENTRAL_USERNAME }}
-          ORG_GRADLE_PROJECT_mavenCentralPassword: ${{ secrets.MAVEN_CENTRAL_PASSWORD }}
-          ORG_GRADLE_PROJECT_signingInMemoryKeyId: ${{ secrets.SIGNING_KEY_ID }}
-          ORG_GRADLE_PROJECT_signingInMemoryKeyPassword: ${{ secrets.SIGNING_PASSWORD }}
-          ORG_GRADLE_PROJECT_signingInMemoryKey: ${{ secrets.GPG_KEY_CONTENTS }}
-

.gitignore

@@ -14,3 +14,5 @@ xcuserdata
 .gigaide
 /kotlin-js-store/yarn.lock
 /test.lyng
+/sample_texts/1.txt.gz
+/kotlin-js-store/wasm/yarn.lock

.run/lyng_site [jsBrowserDevelopmentRun].run.xml

@@ -0,0 +1,24 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="lyng:site [jsBrowserDevelopmentRun]" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$/site" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="--continuous" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value="jsBrowserDevelopmentRun" />
+        </list>
+      </option>
+      <option name="vmOptions" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>true</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <RunAsTest>false</RunAsTest>
+    <method v="2" />
+  </configuration>
+</component>

CHANGELOG.md

@@ -0,0 +1,45 @@
+## Changelog
+
+### Unreleased
+
+- Language: Named arguments and named splats
+  - New call-site syntax for named arguments using colon: `name: value`.
+    - Positional arguments must come before named; positionals after a named argument inside parentheses are rejected.
+    - Trailing-lambda interaction: if the last parameter is already assigned by name (or via a named splat), a trailing `{ ... }` block is illegal.
+  - Named splats: `...` can now expand a Map into named arguments.
+    - Only string keys are allowed; non-string keys raise a clear error.
+    - Duplicate assignment across named args and named splats is an error.
+    - Ellipsis (variadic) parameters remain positional-only and cannot be named.
+  - Rationale: `=` is assignment and an expression in Lyng; `:` at call sites avoids ambiguity. Declarations keep `name: Type`; call-site casts continue to use `as` / `as?`.
+  - Documentation updated: proposals and declaring-arguments sections now cover named args/splats and error cases.
+  - Tests added covering success cases and errors for named args/splats and trailing-lambda interactions.
+
+- Tooling: Highlighters and TextMate bundle updated for named args
+  - Website/editor highlighter (lyngweb + site) works with `name: value` and `...Map("k" => v)`; added JS tests covering punctuation/operator spans for `:` and `...`.
+  - TextMate grammar updated to recognize named call arguments: `name: value` after `(` or `,` with `name` highlighted as `variable.parameter.named.lyng` and `:` as punctuation; excludes `::`.
+  - TextMate bundle version bumped to 0.0.3; README updated with details and guidance.
+
+- Multiple Inheritance (MI) completed and enabled by default:
+  - Active C3 Method Resolution Order (MRO) for deterministic, monotonic lookup across complex hierarchies and diamonds.
+  - Qualified dispatch:
+    - `this@Type.member(...)` inside class bodies starts lookup at the specified ancestor.
+    - Cast-based disambiguation: `(expr as Type).member(...)`, `(expr as? Type)?.member(...)` (works with existing safe-call `?.`).
+  - Field inheritance (`val`/`var`) under MI:
+    - Instance storage is disambiguated per declaring class; unqualified read/write resolves to the first match in MRO.
+    - Qualified read/write targets the chosen ancestor’s storage.
+  - Constructors and initialization:
+    - Direct bases are initialized left-to-right; each ancestor is initialized at most once (diamond-safe de-duplication).
+    - Header-specified constructor arguments are passed to direct bases.
+  - Visibility enforcement under MI:
+    - `private` visible only inside the declaring class body.
+    - `protected` visible inside the declaring class and any of its transitive subclasses; unrelated contexts cannot access it (qualification/casts do not bypass).
+  - Diagnostics improvements:
+    - Missing member/field messages include receiver class and linearization order; hints for `this@Type` or casts when helpful.
+    - Invalid `this@Type` reports that the qualifier is not an ancestor and shows the receiver lineage.
+    - `as`/`as?` cast errors include actual and target type names.
+
+- Documentation updated (docs/OOP.md and tutorial quick-start) to reflect MI with active C3 MRO.
+
+Notes:
+- Existing single-inheritance code continues to work; resolution reduces to the single base.
+- If code previously relied on non-deterministic parent set iteration, C3 MRO provides a predictable order; disambiguate explicitly if needed using `this@Type`/casts.

NOTICE

@@ -0,0 +1,3 @@
+The Lyng programming language.
+Copyright (c) 2024-2025 Sergey Chernov real.sergeych@gmail.com
+

README.md

@@ -1,57 +1,101 @@
 # Lyng: modern scripting for kotlin multiplatform
 
-A KMP library and a standalone interpreter
+Please visit the project homepage: [https://lynglang.com](https://lynglang.com)
 
-- simple, compact, intuitive and elegant modern code style:
+A KMP library and a standalone interpreter. v1.0.0-SNAPSHOT is now available.
+
+- simple, compact, intuitive and elegant modern code:
 
 ```
 class Point(x,y) {
    fun dist() { sqrt(x*x + y*y) } 
 }
 Point(3,4).dist() //< 5
+
+fun swapEnds(first, args..., last, f) {
+    f( last, ...args, first)
+} 
 ```
 
-- extremely simple Kotlin integration on any platform
+- extremely simple Kotlin integration on any platform (JVM, JS, WasmJS, Lunux, MacOS, iOS, Windows)
 - 100% secure: no access to any API you didn't explicitly provide
-- 100% coroutines! Every function/script is a coroutine, it does not block the thread, no async/await/suspend keyword garbage:
+- 100% coroutines! Every function/script is a coroutine, it does not block the thread, no async/await/suspend keyword garbage, see [parallelism]
 
 ```
+  val deferred = launch {
     delay(1.5) // coroutine is delayed for 1.5s, thread is not blocked!
+    "done"
+  }
+  // ...
+  // suspend current coroutine, no thread is blocked again,
+  // and wait for deferred to return something:
+  assertEquals("donw", deferred.await())
 ```
 and it is multithreaded on platforms supporting it (automatically, no code changes required, just
-`launch` more coroutines and they will be executed concurrently if possible)/
+`launch` more coroutines and they will be executed concurrently if possible). See [parallelism]
 
 - functional style and OOP together, multiple inheritance, implementing interfaces for existing classes, writing extensions.
-- Any unicode letters can be used as identifiers: `assert( sin(π/2) == 1 )`.
+- Any Unicode letters can be used as identifiers: `assert( sin(π/2) == 1 )`.
 
  ## Resources: 
 
 - [introduction and tutorial](docs/tutorial.md) - start here please
 - [Samples directory](docs/samples)
+- [Books directory](docs)
 
 ## Integration in Kotlin multiplatform
 
-### Add library
+### Add dependency to your project
 
-TBD
+```kotlin
+// update to current please:
+val lyngVersion = "0.6.1-SNAPSHOT"
+
+repositories {
+    // ...
+    maven("https://gitea.sergeych.net/api/packages/SergeychWorks/maven")
+}
+```
+
+And add dependency to the proper place in your project, it could look like:
+
+```kotlin
+comminMain by getting {
+    dependencies {
+        // ...
+        implementation("net.sergeych:lynglib:$lyngVersion")
+    }
+}
+```
+
+Now you can import lyng and use it:
 
 ### Execute script:
 
 ```kotlin
-assertEquals("hello, world", eval(""" 
+import net.sergeyh.lyng.*
-    "hello, " + "world" 
+
-    """).toString())
+// we need a coroutine to start, as Lyng
+// is a coroutine based language, async topdown
+runBlocking {
+    assert(5 == eval(""" 3*3 - 4 """).toInt())
+    eval(""" println("Hello, Lyng!") """)
+}
 ```
 
 ### Exchanging information
 
-Script is executed over some `Context`. Create instance of the context,
+Script is executed over some `Scope`. Create instance,
-add your specific vars and functions to it, an call over it:
+add your specific vars and functions to it, and call:
 
 ```kotlin
+
+import com.sun.source.tree.Scope
+import new.sergeych.lyng.*
+
 // simple function
-val context = Context().apply {
+val scope = Script.newScope().apply {
-    addFn("addArgs") {
+    addFn("sumOf") {
         var sum = 0.0
         for (a in args) sum += a.toDouble()
         ObjReal(sum)
@@ -62,14 +106,16 @@ val context = Context().apply {
     // suspend fun doSomeWork(text: String): Int
     addFn("doSomeWork") {
         // this _is_ a suspend lambda, we can call suspend function,
-        // and it won't consume the thread:
+        // and it won't consume the thread.
-        doSomeWork(args[0].toString()).toObj()
+        // note that in kotlin handler, `args` is a list of `Obj` arguments
+        // and return value from this lambda should be Obj too:
+        doSomeWork(args[0]).toObj()
     }
 }
 // adding constant:
-context.eval("addArgs(1,2,3)") // <- 6
+scope.eval("sumOf(1,2,3)") // <- 6
 ```
-Note that the context stores all changes in it so you can make calls on a single context to preserve state between calls.
+Note that the scope stores all changes in it so you can make calls on a single scope to preserve state between calls.
 
 ## Why? 
 
@@ -83,22 +129,69 @@ Designed to add scripting to kotlin multiplatform application in easy and effici
 
 # Language 
 
-- dynamic 
+- Javascript, WasmJS, native, JVM, android - batteries included.
-- async
+- dynamic types in most elegant and concise way
-- multithreaded (coroutines could be dispatched using threads on appropriate platforms, automatically)
+- async, 100% coroutines, supports multiple cores where platform supports thread
+- good for functional an object-oriented style
 
-## By-stage
+# Language Roadmap
 
-Here are plans to develop it:
+```mermaid
+flowchart
+    v0([the idea])
+    v1([v1: make it happen])
+    v2([v1.5: testmake it fasted and rich featured])
+    v3([v2: ideal script language])
+    v0 --code MVP--> v1
+    v1 --refine and extend--> v2
+    v2 -- optimize --> v3
     
-### First stage
+```
 
-Interpreted, precompiled into threaded code, actually. Dynamic types.
+## v1.0.0 "Make it happen" - done!
 
-### Second stage
+Planned autumn 2025. Complete dynamic language with sufficient standard library:
 
-Will add:
+Ready features:
 
-- optimizations
+- [x] Language platform and independent command-line launcher
-- p-code serialization
+- [x] Integral types and user classes, variables and constants, functions
-- static typing
+- [x] lambdas and closures, coroutines for all callables
+- [x] while-else, do-while-else, for-else loops with break-continue returning values and labels support
+- [x] ranges, lists, strings, interfaces: Iterable, Iterator, Collection, Array
+- [x] when(value), if-then-else
+- [x] exception handling: throw, try-catch-finally, exception classes.
+- [x] multiplatform maven publication
+- [x] documentation for the current state
+- [x] maps, sets and sequences (flows?)
+- [x] modules
+- [x] string formatting and tools
+- [x] launch, deferred, CompletableDeferred, Mutex, etc.
+- [x] multiline strings
+- [x] typesafe bit-effective serialization
+- [x] compression/decompression (integrated in serialization)
+- [x] dynamic fields
+- [x] function annotations
+- [x] better stack reporting
+- [x] regular exceptions + extended `when`
+- [x] multiple inheritance for user classes
+
+## plan: v1.0 - v1.5 Stability, integration, optimizations
+
+- [x] site with integrated interpreter to give a try
+- [x] kotlin part public API good docs, integration focused
+- [ ] type specifications
+- [ ] language server or compose-based lyng-aware editor
+- [ ] source docs and maybe lyng.md to a standard
+- [ ] metadata first class access from lyng
+- [x] aggressive optimizations
+- [ ] JVM bytecode optimizations
+
+## After 1.5 "Ideal scripting"
+
+  Estimated winter 2027
+
+- [ ] client with GUI support based on compose multiplatform somehow
+- [ ] notebook - style workbooks with graphs, formulae, etc.
+
+[parallelism]: docs/parallelism.md

bin/deploy_site

@@ -0,0 +1,105 @@
+#!/bin/bash
+
+#
+# Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+#
+
+function checkState() {
+  if [[ $? != 0 ]]; then
+    echo
+    echo -- rsync failed. deploy was not finished. deployed version has not been affected
+    echo
+    exit 100
+  fi
+
+}
+
+# default target settings
+case "com" in
+  com)
+    SSH_HOST=sergeych@lynglang.com # host to deploy to
+    SSH_PORT=22                             # ssh port on it
+    ROOT=/bigstore/sergeych_pub/lyng                 # directory to rsync to
+    ;;
+#  com)
+#    SSH_HOST=vvk@front-01.neurodatalab.com
+#    ROOT=/home/vvk
+#    ;;
+  *)
+    echo "*** ERROR: target not specified (use deploy com | dev)"
+    echo "*** stop"
+    exit 101
+esac
+
+die() { echo "ERROR: $*" 1>&2 ; exit 1; }
+
+./gradlew site:clean site:jsBrowserDistribution || die "compilation failed"
+
+if [[ $? != 0 ]]; then
+  echo
+  echo -- build failed. deploy aborted.
+  echo
+  exit 100
+fi
+
+#exit 0
+
+# Prepare working dir
+ssh -p ${SSH_PORT} ${SSH_HOST} "
+  cd ${ROOT}
+  rm -rd build 2>/dev/null
+  if [ -d release ]; then
+    echo copying current release
+    cp -r release build
+  else
+    echo creating first release
+    mkdir release
+    mkdir build
+  fi
+";
+
+# sync files
+SRC=./site/build/dist/js/productionExecutable
+rsync -e "ssh -p ${SSH_PORT}" -avz -r -d --delete ${SRC}/* ${SSH_HOST}:${ROOT}/build/dist
+checkState
+#rsync -e "ssh -p ${SSH_PORT}" -avz  ./static/* ${SSH_HOST}:${ROOT}/build/dist
+#checkState
+#rsync -e "ssh -p ${SSH_PORT}" -avz -r -d --delete private_data/* ${SSH_HOST}:${ROOT}/build/private_data
+#checkState
+
+echo
+echo finalizing the deploy...
+ssh -p ${SSH_PORT} ${SSH_HOST} "
+  cd ${ROOT}
+  rm -rd release~
+  mv release release~
+  mv build release
+  cd release
+  # in this project we needn't restart back when we deploy the front
+  #  ~/bin/restart_service
+";
+
+if [[ $? != 0 ]]; then
+  echo
+  echo -- finalization failed. the rease might be corrupt. rolling back is not yet implemented.
+  echo
+  exit 100
+fi
+
+echo
+echo Deploy successful
+echo
+

bin/local_jrelease

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+#
+# Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+#
+
+set -e
+
+root=./lyng/build/install/lyng-jvm/
+
+./gradlew :lyng:installJvmDist
+#strip $file
+#upx   $file
+rm -rf ~/bin/jlyng-jvm || true
+rm ~/bin/jlyng 2>/dev/null || true
+mkdir -p ~/bin/jlyng-jvm
+cp -R $root ~/bin/jlyng-jvm
+ln -s ~/bin/jlyng-jvm/lyng-jvm/bin/lyng ~/bin/jlyng

bin/local_release

@@ -1,5 +1,22 @@
 #!/bin/bash
 
+#
+# Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+#
+
 set -e
 
 file=./lyng/build/bin/linuxX64/releaseExecutable/lyng.kexe

bin/lyng_test

@@ -0,0 +1,3 @@
+#!/usr/bin/env lyng
+
+println("Hello from lyng!")

build.gradle.kts

@@ -1,3 +1,20 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
 plugins {
     alias(libs.plugins.androidLibrary) apply false
     alias(libs.plugins.kotlinMultiplatform) apply  false

docs/Array.md

@@ -0,0 +1,37 @@
+# Array
+
+It's an interface if the [Collection] that provides indexing access, like `array[3] = 0`.
+Array therefore implements [Iterable] too. The well known implementatino of the `Array` is
+[List].
+
+Array adds the following methods:
+
+## Binary search
+
+When applied to sorted arrays, binary search allow to quicly find an index of the element in the array, or where to insert it to keep order:
+
+    val coll = [1,2,3,4,5]
+    assertEquals( 2, coll.binarySearch(3) )
+    assertEquals( 0, coll.binarySearch(1) )
+    assertEquals( 4, coll.binarySearch(5) )
+
+    val src = (1..50).toList().shuffled()
+    val result = []
+    for( x in src ) {
+        val i = result.binarySearch(x)
+        assert( i < 0 )
+        result.insertAt(-i-1, x)
+    }
+    assertEquals( src.sorted(), result )
+    >>> void
+
+So `binarySearch(x)` returns:
+
+- index of `x`, a non-negative number
+- negative: `x` not found, but if inserted at position `-returnedValue-1` will leave array sorted.
+
+To pre-sort and array use `Iterable.sorted*` or in-place `List.sort*` families, see [List] and [Iterable] docs.
+
+[Collection]: Collection.md
+[Iterable]: Iterable.md
+[List]: List.md

docs/Buffer.md

@@ -0,0 +1,151 @@
+# Binary `Buffer`
+
+Buffers are effective unsigned byte arrays of fixed size. Buffers content is mutable,
+unlike its size. Buffers are comparable and implement [Array], thus [Collection] and [Iterable]. Buffer iterators return
+its contents as unsigned bytes converted to `Int`
+
+Buffers needs to be imported with `import lyng.buffer`:
+
+    import lyng.buffer
+
+    assertEquals(5, Buffer("Hello").size)
+    >>> void
+
+Buffer is _immutable_, there is a `MutableBuffer` with same interface but mutable.
+
+## Constructing
+
+There are a lo of ways to construct a buffer:
+
+    import lyng.buffer
+    
+    // from string using utf8 encoding:
+    assertEquals( 5, Buffer("hello").size )
+
+    // from bytes, e.g. integers in range 0..255
+    assertEquals( 255, Buffer(1,2,3,255).last() )
+
+    // from whatever iterable that produces bytes, e.g.
+    // integers in 0..255 range:
+    assertEquals( 129, Buffer([1,2,129]).last() )
+
+    // Empty buffer of fixed size:
+    assertEquals(100, Buffer(100).size)
+    assertEquals(0, Buffer(100)[0])
+
+    // Note that you can use list iteral to create buffer with 1 byte:
+    assertEquals(1, Buffer([100]).size)
+    assertEquals(100, Buffer([100])[0])
+
+    >>> void
+
+## Accessing and modifying
+
+Buffer implement [Array] and therefore can be accessed, and `MutableBuffers` also modified:
+
+    import lyng.buffer
+    val b1 = Buffer( 1, 2, 3)
+    assertEquals( 2, b1[1] )
+
+    val b2 = b1.toMutable()
+    assertEquals( 2, b1[1] )
+    b2[1]++
+    b2[0] = 100
+    assertEquals( Buffer(100, 3, 3), b2)
+
+    // b2 is a mutable copy so b1 has not been changed:
+    assertEquals( Buffer(1, 2, 3), b1)
+
+    >>> void
+
+Buffer provides concatenation with another Buffer:
+
+    import lyng.buffer
+    val b = Buffer(101, 102)
+    assertEquals( Buffer(101, 102, 1, 2), b + [1,2])
+    >>> void
+
+Please note that indexed bytes are _readonly projection_, e.g. you can't modify these with
+
+## Comparing
+
+Buffers are comparable with other buffers (and notice there are _mutable_ buffers, bu default buffers ar _immutable_):
+
+    import lyng.buffer
+    val b1 = Buffer(1, 2, 3)
+    val b2 = Buffer(1, 2, 3)
+    val b3 = MutableBuffer(b2)
+    
+    b3[0] = 101
+
+    assert( b3 > b1 )
+    assert( b2 == b1 )
+    // longer string with same prefix is considered bigger:
+    assert( b2 + "!".characters() > b1 )
+    // note that characters() provide Iterable of characters that 
+    // can be concatenated to Buffer
+
+    >>> void
+
+## Slicing
+
+As with [List], it is possible to use ranges as indexes to slice a Buffer:
+
+    import lyng.buffer
+
+    val a = Buffer( 100, 101, 102, 103, 104, 105 )
+    assertEquals( a[ 0..1 ], Buffer(100, 101) )
+    assertEquals( a[ 0 ..< 2 ], Buffer(100, 101) )
+    assertEquals( a[  ..< 2 ], Buffer(100, 101) )
+    assertEquals( a[  4.. ], Buffer(104, 105) )
+    assertEquals( a[  2..3 ], Buffer(102, 103) )
+
+    >>> void
+
+## Encoding
+
+You can encode `String` to buffer using buffer constructor, as was shown. Also, buffer supports out of the box base64 (
+which is used in `toString`) and hex encoding:
+
+    import lyng.buffer
+    
+    // to UTF8 and back:
+    val b = Buffer("hello")
+    assertEquals( "hello", b.decodeUtf8() )
+    
+    // to base64 and back:
+    assertEquals( b, Buffer.decodeBase64(b.base64) )
+    assertEquals( b, Buffer.decodeHex(b.hex) )
+    >>> void
+
+## Members
+
+| name                       | meaning                                 | type          |
+|----------------------------|-----------------------------------------|---------------|
+| `size`                     | size                                    | Int           |
+| `decodeUtf8`               | decode to String using UTF8 rules       | Any           |
+| `+`                        | buffer concatenation                    | Any           |
+| `toMutable()`              | create a mutable copy                   | MutableBuffer |
+| `hex`                      | encode to hex strign                    | String        |
+| `Buffer.decodeHex(hexStr)  | decode hex string                       | Buffer        |
+| `base64`                   | encode to base64 (url flavor) (2)       | String        |
+| `Buffer.decodeBase64(str)` | decode base64 to new Buffer (2)         | Buffer        |
+| `toBitInput()`             | create bit input from a byte buffer (3) |               |
+
+(1)
+: optimized implementation that override `Iterable` one
+
+(2)
+: base64url alphabet is used without trailing '=', which allows string to be used in URI without escaping. Note that
+decoding supports both traditional and URL alphabets automatically, and ignores filling `=` characters. Base64URL is
+well known and mentioned in the internet, for example, [here](https://base64.guru/standards/base64url).
+
+(3)
+: `BitInput` is a bit buffer that is used, for example, in [Lynon.decode](serialization.md)
+
+Also, it inherits methods from [Iterable] and [Array].
+
+
+[Range]: Range.md
+
+[Iterable]: Iterable.md

docs/Collection.md

@@ -0,0 +1,19 @@
+# Collection
+
+Is a [Iterable] with known `size`, a finite [Iterable]:
+
+    class Collection : Iterable {
+        val size
+    }
+
+| name                   | description                                          |
+|------------------------|------------------------------------------------------|
+
+(1)
+: `comparator(a,b)` should return -1 if `a < b`, +1 if `a > b` or zero.
+
+See [List], [Set] and [Iterable]
+
+[Iterable]: Iterable.md
+[List]: List.md
+[Set]: Set.md

docs/Iterable.md

@@ -1,37 +1,141 @@
 # Iterable interface
 
-The inteface which requires iterator to be implemented:
+The interface for anything that can be iterated, e.g. finite or infinite ordered set of data that can be accessed
+sequentially. Almost any data container in `Lyng` implements it: `List`, `Set`, `Buffer`, `RingBuffer`, `BitBuffer`,
+`Range` and many others are `Iterable`, also `Collection` and `Array` interfaces inherit it.
 
-    fun iterator(): Iterator
+`Map` and `String` have `Iterable` members to access its contents too.
+
+Please see also [Collection] interface: many iterables are also collections, and it adds important features.
+
+## Definition:
+
+Iterable is a class that provides function that creates _the iterator_:
+
+    class Iterable {
+        abstract fun iterator()
+    }
+
+Note that each call of `iterator()` must provide an independent iterator.
 
 Iterator itself is a simple interface that should provide only to method:
 
-    interface Iterable {
+    class Iterator {
-        fun hasNext(): Bool
+        abstract fun hasNext(): Bool
         fun next(): Obj
     }
 
 Just remember at this stage typed declarations are not yet supported.
 
-Having `Iterable` in base classes allows to use it in for loop. Also, each `Iterable` has some utility functions available:
+Having `Iterable` in base classes allows to use it in for loop. Also, each `Iterable` has some utility functions
+available, for example
 
-## Abstract methods
+    val r = 1..10  // Range is Iterable!  
+    assertEquals( [9,10], r.takeLast(2).toList() )
+    assertEquals( [1,2,3], r.take(3).toList() )
+    assertEquals( [9,10], r.drop(8).toList() )
+    assertEquals( [1,2], r.dropLast(8).toList() )
+    >>> void
+
+## joinToString
+
+This methods convert any iterable to a string joining string representation of each element, optionally transforming it
+and joining using specified suffix.
+
+    Iterable.joinToString(suffux=' ', transform=null)
+
+- if `Iterable` `isEmpty`, the empty string `""` is returned.
+- `suffix` is inserted between items when there are more than one.
+- `transform` of specified is applied to each element, otherwise its `toString()` method is used.
+
+Here is the sample:
+
+    assertEquals( (1..3).joinToString(), "1 2 3")
+    assertEquals( (1..3).joinToString(":"), "1:2:3")
+    assertEquals( (1..3).joinToString { it * 10 }, "10 20 30")
+    >>> void
+
+## `sum` and `sumBy`
+
+These, again, does the thing:
+
+    assertEquals( 6, [1,2,3].sum() )
+    assertEquals( 12, [1,2,3].sumOf { it*2 } )
+
+    // sum of empty collections is null:
+    assertEquals( null, [].sum() )
+    assertEquals( null, [].sumOf { 2*it } )
+
+    >>> void
+
+## Instance methods:
+
+| fun/method             | description                                                                     |
+|------------------------|---------------------------------------------------------------------------------|
+| toList()               | create a list from iterable                                                     |
+| toSet()                | create a set from iterable                                                      |
+| contains(i)            | check that iterable contains `i`                                                |
+| `i in iterator`        | same as `contains(i)`                                                           |
+| isEmpty()              | check iterable is empty                                                         |
+| forEach(f)             | call f for each element                                                         |
+| toMap()                | create a map from list of key-value pairs (arrays of 2 items or like)           |
+| map(f)                 | create a list of values returned by `f` called for each element of the iterable |
+| indexOf(i)             | return index if the first encounter of i or a negative value if not found       |
+| associateBy(kf)        | create a map where keys are returned by kf that will be called for each element |
+| first                  | first element (1)                                                               |
+| last                   | last element (1)                                                                |
+| take(n)                | return [Iterable] of up to n first elements                                     |
+| taleLast(n)            | return [Iterable] of up to n last elements                                      |
+| drop(n)                | return new [Iterable] without first n elements                                  |
+| dropLast(n)            | return new [Iterable] without last n elements                                   |
+| sum()                  | return sum of the collection applying `+` to its elements (3)                   |
+| sumOf(predicate)       | sum of the modified collection items (3)                                        |
+| sorted()               | return [List] with collection items sorted naturally                            |
+| sortedWith(comparator) | sort using a comparator that compares elements (1)                              |
+| sortedBy(predicate)    | sort by comparing results of the predicate function                             |
+| joinToString(s,t)      | convert iterable to string, see (2)                                             |
+| reversed()             | create a list containing items from this in reverse order                       |
+| shuffled()             | create a listof shiffled elements                                               |
+
+(1)
+: throws `NoSuchElementException` if there is no such element
+
+(2)
+: `joinToString(suffix=" ",transform=null)`: suffix is inserted between items if there are more than one, trasnfom is
+optional function applied to each item that must return result string for an item, otherwise `item.toString()` is used.
+
+(3)
+: sum of empty collection is `null`
+
+    fun Iterable.toList(): List
+    fun Iterable.toSet(): Set
+    fun Iterable.indexOf(element): Int
+    fun Iterable.contains(element): Bool
+    fun Iterable.isEmpty(element): Bool
+    fun Iterable.forEach(block: (Any?)->Void ): Void
+    fun Iterable.map(block: (Any?)->Void ): List
+    fun Iterable.associateBy( keyMaker: (Any?)->Any): Map
+
+## Abstract methods:
 
     fun iterator(): Iterator
 
-## Instance methods
-
-### toList()
-
 Creates a list by iterating to the end. So, the Iterator should be finite to be used with it.
 
 ## Included in interfaces:
 
-- Collection, Array, [List]
+- [Collection], Array, [List]
 
 ## Implemented in classes:
 
-- [List], [Range]
+- [List], [Range], [Buffer](Buffer.md), [BitBuffer], [Buffer], [Set], [RingBuffer]
+
+[Collection]: Collection.md
 
 [List]: List.md
+
 [Range]: Range.md
+
+[Set]: Set.md
+
+[RingBuffer]: RingBuffer.md

docs/Iterator.md

@@ -9,6 +9,9 @@ To implement the iterator you need to implement only two abstract methods:
 
 ### hasNext(): Bool
 
+    // lets test
+    // offset
+
 Should return `true` if call to `next()` will return valid next element.
 
 ### next(): Obj

docs/List.md

@@ -20,11 +20,11 @@ indexing is zero-based, as in C/C++/Java/Kotlin, etc.
     list[1]
     >>> 20
 
-Using negative indexes has a special meaning: _offset from the end of the list_:
+There is a shortcut for the last:
 
     val list = [10, 20, 30]
-    list[-1]
+    [list.last, list.lastIndex]
-    >>> 30
+    >>> [30,2]
 
 __Important__ negative indexes works wherever indexes are used, e.g. in insertion and removal methods too.
 
@@ -38,7 +38,8 @@ You can concatenate lists or iterable objects:
 
 ## Appending
 
-To append to lists, use `+=` with elements, lists and any [Iterable] instances, but beware it will concatenate [Iterable] objects instead of appending them. To append [Iterable] instance itself, use `list.add`:
+To append to lists, use `+=` with elements, lists and any [Iterable] instances, but beware it will
+concatenate [Iterable] objects instead of appending them. To append [Iterable] instance itself, use `list.add`:
 
     var list = [1, 2]
     val other = [3, 4]
@@ -57,7 +58,28 @@ To append to lists, use `+=` with elements, lists and any [Iterable] instances,
 
     >>> void
 
+## Removing elements
 
+List is mutable, so it is possible to remove its contents. To remove a single element
+by index use:
+
+    assertEquals( [1,2,3].removeAt(1), [1,3] )
+    assertEquals( [1,2,3].removeAt(0), [2,3] )
+    assertEquals( [1,2,3].removeLast(), [1,2] )
+    >>> void
+
+There is a way to remove a range (see [Range] for more on ranges):
+
+    assertEquals( [1, 4], [1,2,3,4].removeRange(1..2))
+    assertEquals( [1, 4], [1,2,3,4].removeRange(1..<3))
+    >>> void
+
+Open end ranges remove head and tail elements:
+
+    assertEquals( [3, 4, 5], [1,2,3,4,5].removeRange(..1))
+    assertEquals( [3, 4, 5], [1,2,3,4,5].removeRange(..<2))
+    assertEquals( [1, 2], [1,2,3,4,5].removeRange( (2..) ))
+    >>> void
 
 ## Comparisons
 
@@ -70,21 +92,79 @@ To append to lists, use `+=` with elements, lists and any [Iterable] instances,
     assert( [1, 2, 3] !== [1, 2, 3])
     >>> void
 
+## In-place sort
+
+List could be sorted in place, just like [Collection] provide sorted copies, in a very like way:
+
+    val l1 = [6,3,1,9]
+    l1.sort()
+    assertEquals( [1,3,6,9], l1)
+    
+    l1.sortBy { -it }
+    assertEquals( [1,3,6,9].reversed(), l1)
+    
+    l1.sort() // 1 3 6 9
+    l1.sortBy { it % 4 }
+    // 1,3,6,9 gives, mod 4:
+    // 1 3 2 1
+    // we hope we got it also stable:
+    assertEquals( [1,9,6,3], l1)
+    >>> void
+
 ## Members
 
 | name                          | meaning                                      | type        |
-|-----------------------------------|-------------------------------------|----------|
+|-------------------------------|----------------------------------------------|-------------|
 | `size`                        | current size                                 | Int         |
 | `add(elements...)`            | add one or more elements to the end          | Any         |
-| `addAt(index,elements...)`        | insert elements at position         | Int, Any |
+| `insertAt(index,elements...)` | insert elements at position                  | Int, Any    |
 | `removeAt(index)`             | remove element at position                   | Int         |
-| `removeRangeInclusive(start,end)` | remove range, inclusive (1)         | Int, Int |
+| `remove(from,toNonInclusive)` | remove range from (incl) to (nonincl)        | Int, Int    |
-|                                   |                                     |          |
+| `remove(Range)`               | remove range                                 | Range       |
+| `removeLast()`                | remove last element                          |             |
+| `removeLast(n)`               | remove n last elements                       | Int         |
+| `contains(element)`           | check the element is in the list (1)         |             |
+| `[index]`                     | get or set element at index                  | Int         |
+| `[Range]`                     | get slice of the array (copy)                | Range       |
+| `+=`                          | append element(s) (2)                        | List or Obj |
+| `sort()`                      | in-place sort, natural order                 | void        |
+| `sortBy(predicate)`           | in-place sort bu `predicate` call result (3) | void        |
+| `sortWith(comparator)`        | in-place sort using `comarator` function (4) | void        |
+| `shiffle()`                   | in-place shiffle contents                    |             |
 
 (1)
-: end-inclisiveness allows to use negative indexes to, for exampe, remove several last elements, like `list.removeRangeInclusive(-2, -1)` will remove two last elements.
+: optimized implementation that override `Array` one
+
+(2)
+: `+=` append either a single element, or all elements if the List or other Iterable
+instance is appended. If you want to append an Iterable object itself, use `add` instead.
+
+(3)
+: predicate is called on each element, and the returned values are used to sort in natural
+order, e.g. is same as `list.sortWith { a,b -> predicate(a) <=> predicate(b) }`
+
+(4)
+: comparator callable takes tho arguments and must return: negative value when first is less,
+positive if first is greater, and zero if they are equal. For example, the equvalent comparator
+for `sort()` will be `sort { a, b -> a <=> b }
+
+It inherits from [Iterable] too and thus all iterable methods are applicable to any list.
+
+## Member inherited from Array
+
+| name             | meaning                        | type  |
+|------------------|--------------------------------|-------|
+| `last`           | last element (throws if empty) |       |
+| `lastOrNull`     | last element or null           |       |
+| `lastIndex`      |                                | Int   |
+| `indices`        | range of indexes               | Range |
+| `contains(item)` | test that item is in the list  |       |
+
+(1)
+: end-inclisiveness allows to use negative indexes to, for exampe, remove several last elements, like
+`list.removeRangeInclusive(-2, -1)` will remove two last elements.
 
 
-# Notes
+[Range]: Range.md
 
-Could be rewritten using array as a class but List as the interface
+[Iterable]: Iterable.md

docs/Map.md

@@ -0,0 +1,178 @@
+# Map
+
+Map is a mutable collection of key-value pairs, where keys are unique. You can create maps in two ways:
+- with the constructor `Map(...)` or `.toMap()` helpers; and
+- with map literals using braces: `{ "key": value, id: expr, id: }`.
+
+When constructing from a list, each list item must be a [Collection] with exactly 2 elements, for example, a [List].
+
+Important thing is that maps can't contain `null`: it is used to return from missing elements.
+
+Constructed map instance is of class `Map` and implements `Collection` (and therefore `Iterable`).
+
+    val oldForm = Map( "foo" => 1, "bar" => "buzz" )
+    assert(oldForm is Map)
+    assert(oldForm.size == 2)
+    assert(oldForm is Iterable)
+    >>> void
+
+Notice usage of the `=>` operator that creates `MapEntry`, which also implements [Collection] of
+two items, first, at index zero, is a key, second, at index 1, is the value. You can use lists too.
+Map keys could be any objects (hashable, e.g. with reasonable hashCode, most of standard types are). You can access elements with indexing operator:
+
+    val map = Map( ["foo", 1], ["bar", "buzz"], [42, "answer"] )
+    assert( map["bar"] == "buzz")
+    assert( map[42] == "answer" )
+    assertEquals( null, map["nonexisting"])
+    assert( map.getOrNull(101) == null )
+    assert( map.getOrPut(911) { "nine-eleven" } == "nine-eleven" )
+    // now 91 entry is set:
+    assert( map[911] == "nine-eleven" )
+    map["foo"] = -1
+    assert( map["foo"] == -1)
+    >>> void
+
+## Map literals { ... }
+
+Lyng supports JavaScript-like map literals. Keys can be string literals or identifiers, and there is a handy identifier shorthand:
+
+- String key: `{ "a": 1 }`
+- Identifier key: `{ foo: 2 }` is the same as `{ "foo": 2 }`
+- Identifier shorthand: `{ foo: }` is the same as `{ "foo": foo }`
+
+Access uses brackets: `m["a"]`.
+
+    val x = 10
+    val y = 10
+    val m = { "a": 1, x: x * 2, y: }
+    assertEquals(1, m["a"])      // string-literal key
+    assertEquals(20, m["x"])     // identifier key
+    assertEquals(10, m["y"])     // identifier shorthand expands to y: y
+    >>> void
+
+Trailing commas are allowed for nicer diffs and multiline formatting:
+
+    val m = {
+        "a": 1,
+        b: 2,
+    }
+    assertEquals(1, m["a"]) 
+    assertEquals(2, m["b"]) 
+    >>> void
+
+Empty `{}` is reserved for blocks/lambdas; use `Map()` for an empty map.
+
+To remove item from the collection. use `remove`. It returns last removed item or null. Be careful if you 
+hold nulls in the map - this is not a recommended practice when using `remove` returned value. `clear()` 
+removes all.
+
+    val map = Map( "foo" => 1, "bar" => "buzz", [42, "answer"] )
+    assertEquals( 1, map.remove("foo") )
+    assert( map.getOrNull("foo") == null)
+    assert( map.size == 2 )
+    map.clear()
+    assert( map.size == 0 )
+    >>> void
+
+Map implements [contains] method that checks _the presence of the key_ in the map:
+
+    val map = Map( ["foo", 1], ["bar", "buzz"], [42, "answer"] )
+    assert( "foo" in map )
+    assert( "answer" !in map )
+    >>> void
+
+To iterate maps it is convenient to use `keys` method that returns [Set] of keys (keys are unique:
+
+    val map = Map( ["foo", 1], ["bar", "buzz"], [42, "answer"] )
+    for( k in map.keys ) println(map[k])
+    >>> 1
+    >>> buzz
+    >>> answer
+    >>> void
+
+Or iterate its key-value pairs that are instances of [MapEntry] class:
+
+    val map = Map( ["foo", 1], ["bar", "buzz"], [42, "answer"] )
+    for( entry in map ) {
+        println("map[%s] = %s"(entry.key, entry.value))
+    }
+    void
+    >>> map[foo] = 1
+    >>> map[bar] = buzz
+    >>> map[42] = answer
+    >>> void
+
+There is a shortcut to use `MapEntry` to create maps: operator `=>` which creates `MapEntry`:
+
+    val entry = "answer" => 42
+    assert( entry is MapEntry )
+    >>> void
+
+And you can use it to construct maps:
+
+    val map = Map( "foo" => 1, "bar" => 22)
+    assertEquals(1, map["foo"])
+    assertEquals(22, map["bar"])
+    >>> void
+
+Or use `.toMap` on anything that implements [Iterable] and which elements implements [Array] with 2 elements size, for example, `MapEntry`:
+
+    val map = ["foo" => 1, "bar" => 22].toMap()
+    assert( map is Map )
+    assertEquals(1, map["foo"])
+    assertEquals(22, map["bar"])
+    >>> void
+
+
+It is possible also to get values as [List] (values are not unique):
+
+    val map = Map( ["foo", 1], ["bar", "buzz"], [42, "answer"] )
+    assertEquals(map.values, [1, "buzz", "answer"] )
+    >>> void
+
+Map could be tested to be equal: when all it key-value pairs are equal, the map
+is equal.
+
+    val m1 = Map(["foo", 1])
+    val m2 = Map(["foo", 1])
+    val m3 = Map(["foo", 2])
+    assert( m1 == m2 )
+    // but the references are different:
+    assert( m1 !== m2 )
+    // different maps:
+    assert( m1 != m3 )
+    >>> void
+
+## Spreads and merging
+
+Inside map literals you can spread another map with `...` and items will be merged left-to-right; rightmost wins:
+
+    val base = { a: 1, b: 2 }
+    val m = { a: 0, ...base, b: 3, c: 4 }
+    assertEquals(1, m["a"])  // base overwrites a:0
+    assertEquals(3, m["b"])  // literal overwrites spread
+    assertEquals(4, m["c"])  // new key
+    >>> void
+
+Maps and entries can also be merged with `+` and `+=`:
+
+    val m1 = ("x" => 1) + ("y" => 2)
+    assertEquals(1, m1["x"])
+    assertEquals(2, m1["y"])
+
+    val m2 = { "a": 10 } + ("b" => 20)
+    assertEquals(10, m2["a"])
+    assertEquals(20, m2["b"])
+
+    var m3 = { a: 1 }
+    m3 += ("b" => 2)
+    assertEquals(1, m3["a"])
+    assertEquals(2, m3["b"])
+    >>> void
+
+Notes:
+- Map literals always use string keys (identifier keys are converted to strings).
+- Spreads inside map literals and `+`/`+=` merges require string keys on the right-hand side; this aligns with named-argument splats.
+- When you need computed or non-string keys, use the constructor form `Map(...)` or build entries with `=>` and then merge.
+
+[Collection](Collection.md)

docs/OOP.md

@@ -71,6 +71,99 @@ Functions defined inside a class body are methods, and unless declared
     void
     >>> void
 
+## Multiple Inheritance (MI)
+
+Lyng supports declaring a class with multiple direct base classes. The syntax is:
+
+```
+class Foo(val a) {
+    var tag = "F"
+    fun runA() { "ResultA:" + a }
+    fun common() { "CommonA" }
+    private fun privateInFoo() {}
+    protected fun protectedInFoo() {}
+}
+
+class Bar(val b) {
+    var tag = "B"
+    fun runB() { "ResultB:" + b }
+    fun common() { "CommonB" }
+}
+
+// Multiple inheritance with per‑base constructor arguments
+class FooBar(a, b) : Foo(a), Bar(b) {
+    // You can disambiguate via qualified this or casts
+    fun fromFoo() { this@Foo.common() }
+    fun fromBar() { this@Bar.common() }
+}
+
+val fb = FooBar(1, 2)
+assertEquals("ResultA:1", fb.runA())
+assertEquals("ResultB:2", fb.runB())
+// Unqualified ambiguous member resolves to the first base (leftmost)
+assertEquals("CommonA", fb.common())
+// Disambiguation via casts
+assertEquals("CommonB", (fb as Bar).common())
+assertEquals("CommonA", (fb as Foo).common())
+
+// Field inheritance with name collisions
+assertEquals("F", fb.tag)            // unqualified: leftmost base
+assertEquals("F", (fb as Foo).tag)   // qualified read: Foo.tag
+assertEquals("B", (fb as Bar).tag)   // qualified read: Bar.tag
+
+fb.tag = "X"                         // unqualified write updates leftmost base
+assertEquals("X", (fb as Foo).tag)
+assertEquals("B", (fb as Bar).tag)
+
+(fb as Bar).tag = "Y"                 // qualified write updates Bar.tag
+assertEquals("X", (fb as Foo).tag)
+assertEquals("Y", (fb as Bar).tag)
+```
+
+Key rules and features:
+
+- Syntax
+  - `class Derived(args) : Base1(b1Args), Base2(b2Args)`
+  - Each direct base may receive constructor arguments specified in the header. Only direct bases receive header args; indirect bases must either be default‑constructible or receive their args through their direct child (future extensions may add more control).
+
+- Resolution order (C3 MRO — active)
+  - Member lookup is deterministic and follows C3 linearization (Python‑like), which provides a monotonic, predictable order for complex hierarchies and diamonds.
+  - Intuition: for `class D() : B(), C()` where `B()` and `C()` both derive from `A()`, the C3 order is `D → B → C → A`.
+  - The first visible match along this order wins.
+
+- Qualified dispatch
+  - Inside a class body, use `this@Type.member(...)` to start lookup at the specified ancestor.
+  - For arbitrary receivers, use casts: `(expr as Type).member(...)` or `(expr as? Type)?.member(...)` (safe‑call `?.` is already available in Lyng).
+  - Qualified access does not relax visibility.
+
+- Field inheritance (`val`/`var`) and collisions
+  - Instance storage is kept per declaring class, internally disambiguated; unqualified read/write resolves to the first match in the resolution order (leftmost base).
+  - Qualified read/write (via `this@Type` or casts) targets the chosen ancestor’s storage.
+  - `val` remains read‑only; attempting to write raises an error as usual.
+
+- Constructors and initialization
+  - During construction, direct bases are initialized left‑to‑right in the declaration order. Each ancestor is initialized at most once (diamond‑safe de‑duplication).
+  - Arguments in the header are evaluated in the instance scope and passed to the corresponding direct base constructor.
+  - The most‑derived class’s constructor runs after the bases.
+
+- Visibility
+  - `private`: accessible only inside the declaring class body; not visible in subclasses and cannot be accessed via `this@Type` or casts.
+  - `protected`: accessible in the declaring class and in any of its transitive subclasses (including MI), but not from unrelated contexts; qualification/casts do not bypass it.
+
+- Diagnostics
+  - When a member/field is not found, error messages include the receiver class name and the considered linearization order, with suggestions to disambiguate using `this@Type` or casts if appropriate.
+  - Qualifying with a non‑ancestor in `this@Type` reports a clear error mentioning the receiver lineage.
+  - `as`/`as?` cast errors mention the actual and target types.
+
+Compatibility notes:
+
+- Existing single‑inheritance code continues to work unchanged; its resolution order reduces to the single base.
+- If your previous code accidentally relied on non‑deterministic parent set iteration, it may change behavior — the new deterministic order is a correctness fix.
+
+### Migration note (declaration‑order → C3)
+
+Earlier drafts and docs described a declaration‑order depth‑first linearization. Lyng now uses C3 MRO for member lookup and disambiguation. Most code should continue to work unchanged, but in rare edge cases involving diamonds or complex multiple inheritance, the chosen base for an ambiguous member may change to reflect C3. If needed, disambiguate explicitly using `this@Type.member(...)` inside class bodies or casts `(expr as Type).member(...)` from outside.
+
 ## fields and visibility
 
 It is possible to add non-constructor fields:
@@ -130,6 +223,25 @@ Private fields are visible only _inside the class instance_:
     void
     >>> void
 
+### Protected members
+
+Protected members are available to the declaring class and all of its transitive subclasses (including via MI), but not from unrelated contexts:
+
+```
+class A() {
+    protected fun ping() { "pong" }
+}
+class B() : A() {
+    fun call() { this@A.ping() }
+}
+
+val b = B()
+assertEquals("pong", b.call())
+
+// Unrelated access is forbidden, even via cast
+assertThrows { (b as A).ping() }
+```
+
 It is possible to provide private constructor parameters so they can be
 set at construction but not available outside the class:
 
@@ -147,7 +259,7 @@ In many cases it is necessary to implement custom comparison and `toString`, sti
 each class is provided with default implementations:
 
 - default toString outputs class name and its _public_ fields.
-- default comparison compares compares all public fields in order of appearance.
+- default comparison compares all fields in order of appearance.
 
 For example, for our class Point:
 
@@ -160,6 +272,185 @@ For example, for our class Point:
     Point(1,1+1)
     >>> Point(x=1,y=2)
 
+## Statics: class fields and class methods
+
+You can mark a field or a method as static. This is borrowed from Java as more plain version of a kotlin's companion object or Scala's object. Static field and functions is one for a class, not for an instance. From inside the class, e.g. from the class method, it is a regular var. From outside, it is accessible as `ClassName.field` or method:
+
+
+    class Value(x) {
+        static var foo = Value("foo")
+
+        static fun exclamation() {
+            // here foo is a regular var:
+            foo.x + "!"
+        }
+    }
+    assertEquals( Value.foo.x, "foo" )
+    assertEquals( "foo!", Value.exclamation() )
+
+    // we can access foo from outside like this:
+    Value.foo = Value("bar")
+    assertEquals( "bar!", Value.exclamation() )
+    >>> void
+
+As usual, private statics are not accessible from the outside:
+
+    class Test {
+        // private, inacessible from outside protected data:
+        private static var data = null
+
+        // the interface to access and change it:
+        static fun getData() { data }
+        static fun setData(value) { data = value }
+    }
+
+    // no direct access:
+    assertThrows { Test.data }
+
+    // accessible with the interface:
+    assertEquals( null, Test.getData() )
+    Test.setData("fubar")
+    assertEquals("fubar", Test.getData() )
+    >>> void
+
+# Extending classes
+
+It sometimes happen that the class is missing some particular functionality that can be _added to it_ without rewriting its inner logic and using its private state. In this case _extension methods_ could be used, for example. we want to create an extension method
+that would test if some object of unknown type contains something that can be interpreted
+as an integer. In this case we _extend_ class `Object`, as it is the parent class for any instance of any type:
+
+        fun Object.isInteger() {
+            when(this) {
+                // already Int?
+                is Int -> true
+
+                // real, but with no declimal part?
+                is Real -> toInt() == this
+
+                // string with int or real reuusig code above
+                is String -> toReal().isInteger()
+                
+                // otherwise, no:
+                else -> false
+            }
+        }
+
+        // Let's test:        
+        assert( 12.isInteger() == true )
+        assert( 12.1.isInteger() == false )
+        assert( "5".isInteger() )
+        assert( ! "5.2".isInteger() )
+        >>> void
+
+__Important note__ as for version 0.6.9, extensions are in __global scope__. It means, that once applied to a global type (Int in our sample), they will be available for _all_ contexts, even new created, 
+as they are modifying the type, not the context.
+
+Beware of it. We might need to reconsider it later.
+
+## dynamic symbols
+
+Sometimes it is convenient to provide methods and variables whose names are not known at compile time. For example, it could be external interfaces not known to library code, user-defined data fields, etc. You can use `dynamic` function to create such:
+
+    // val only dynamic object
+    val accessor = dynamic {
+        // all symbol reads are redirected here:
+        get { name ->
+            // lets provide one dynamic symbol:
+            if( name == "foo" ) "bar" else null
+            // consider also throw SymbolNotDefinedException
+        }
+    }
+    
+    // now we can access dynamic "fields" of accessor:
+    assertEquals("bar", accessor.foo)
+    assertEquals(null, accessor.bar)
+    >>> void
+
+The same we can provide writable dynamic fields (var-type), adding set method:
+
+    // store one dynamic field here
+    var storedValueForBar = null
+    
+    // create dynamic object with 2 fields:
+    val accessor = dynamic {
+        get { name ->
+            when(name) {
+                // constant field
+                "foo" -> "bar"
+                // mutable field
+                "bar" -> storedValueForBar 
+
+                else -> throw SymbolNotFoundException()
+            }
+        }
+        set { name, value ->
+            // only 'bar' is mutable:
+            if( name == "bar" )
+                storedValueForBar = value
+                // the rest is immotable. consider throw also
+                // SymbolNotFoundException when needed.
+            else throw IllegalAssignmentException("Can't assign "+name)
+        }
+    }
+    
+    assertEquals("bar", accessor.foo)
+    assertEquals(null, accessor.bar)
+    accessor.bar = "buzz"
+    assertEquals("buzz", accessor.bar)
+    
+    assertThrows {
+        accessor.bad = "!23"
+    }
+    void
+    >>> void
+
+Of course, you can return any object from dynamic fields; returning lambdas let create _dynamic methods_ - the callable method. It is very convenient to implement libraries with dynamic remote interfaces, etc.
+
+### Dynamic indexers
+
+Index access for dynamics is passed to the same getter and setter, so it is
+generally the same:
+
+    var storedValue = "bar"
+    val x = dynamic {
+        get { 
+            if( it == "foo" ) storedValue
+            else null
+        }
+    }
+    assertEquals("bar", x["foo"] )
+    assertEquals("bar", x.foo )
+    >>> void
+
+And assigning them works the same. You can make it working
+mimicking arrays, but remember, it is not Collection so
+collection's sugar won't work with it:
+
+    var storedValue = "bar"
+    val x = dynamic {
+        get { 
+            when(it) {
+                "size" -> 1
+                0 -> storedValue
+                else -> null
+            }
+        }
+        set { index, value -> 
+            if( index == 0 ) storedValue = value
+            else throw "Illegal index: "+index
+        }
+    }
+    assertEquals("bar", x[0] )
+    assertEquals(1, x.size )
+    x[0] = "buzz"
+    assertThrows { x[1] = 1 }
+    assertEquals("buzz", storedValue)
+    assertEquals("buzz", x[0])
+    >>> void
+
+If you want dynamic to function like an array, create a [feature
+request](https://gitea.sergeych.net/SergeychWorks/lyng/issues).
+
 # Theory
 
 ## Basic principles:
@@ -216,11 +507,10 @@ Note `Real` class: it is global variable for Real class; there are such class in
     assert('$'::class == Char)
     >>> void
 
-More complex is singleton classes, because you don't need to compare their class
+Singleton classes also have class:
-instances and generally don't need them at all, these are normally just Obj:
 
     null::class
-    >>> Obj
+    >>> Null
 
 At this time, `Obj` can't be accessed as a class.
 

docs/Range.md

@@ -87,7 +87,7 @@ You can use Char as both ends of the closed range:
 Exclusive end char ranges are supported too:
 
     ('a'..<'c').toList 
-    >>> ['a', 'b']
+    >>> [a,b]
 
 
 # Instance members

docs/Real.md

@@ -16,9 +16,9 @@ you can use it's class to ensure type:
 ## Member functions
 
 | name            | meaning                                                     | type |
-|-----------------|------------------------------------|------|
+|-----------------|-------------------------------------------------------------|------|
 | `.roundToInt()` | round to nearest int like round(x)                          | Int  |
-|                 |                                    |      |
+| `.toInt()`      | convert integer part of real to `Int` dropping decimal part | Int  |
 |                 |                                                             |      |
 |                 |                                                             |      |
 |                 |                                                             |      |

docs/Regex.md

@@ -0,0 +1,91 @@
+# Regular expressions
+
+In lyng, you create regular expressions using class `Regex` or `String.re` methods:
+
+    assert( "\d*".re is Regex )
+    assert( Regex("\d*") is Regex )
+    >>> void
+
+We plan to add slash syntax at some point.
+
+To check that some string matches as whole to some regex:
+
+    assert( "123".matches("\d{3}".re) )
+    assert( !"123".matches("\d{4}".re) )
+    assert( !"1234".matches("\d".re) )
+    >>> void
+
+To check that _part of the string_ matches some regular expession, use _match operator_ `=~` just like in Ruby, and its
+counterpart, _not match_ operator `!~`:
+
+    assert( "abc123def" =~ "\d\d\d".re )
+    assert( "abc" !~ "\d\d\d".re )
+    >>> void
+
+When you need to find groups, and more detailed match information, use `Regex.find`:
+
+    val result = Regex("abc(\d)(\d)(\d)").find( "bad456 good abc123")
+    assert( result  != null )
+    assertEquals( 12 .. 17, result.range )
+    assertEquals( "abc123", result[0] )
+    assertEquals( "1", result[1] )
+    assertEquals( "2", result[2] )
+    assertEquals( "3", result[3] )
+    >>> void
+
+Note that the object `RegexMatch`, returned by [Regex.find], behaves much like in many other languages: it provides the
+index range and groups matches as indexes.
+
+Match operator actually also provides `RegexMatch` in `$~` reserved variable (borrowed from Ruby too):
+
+    assert( "bad456 good abc123" =~ "abc(\d)(\d)(\d)".re )
+    assertEquals( 12 .. 17, $~.range )
+    assertEquals( "abc123", $~[0] )
+    assertEquals( "1", $~[1] )
+    assertEquals( "2", $~[2] )
+    assertEquals( "3", $~[3] )
+    >>> void
+
+This is often more readable than calling `find`.
+
+Note that `=~` and `!~` operators against strings and regular expressions are commutative, e.g. regular expression and a
+string can be either left or right operator, but not both:
+
+    assert( "abc" =~ "\wc".re )
+    assert( "abc" !~ "\w1c".re )
+    assert( "a\wc".re =~ "abcd" )
+    assert( "a[a-z]c".re !~ "a2cd" )
+    >>> void
+
+Also, string indexing is Regex-aware, and works like `Regex.find` (_not findall!_):
+
+    assert( "cd" == "abcdef"[ "c.".re ].value )
+    >>> void
+
+
+# Regex class reference
+
+| name         | description                         | notes |
+|--------------|-------------------------------------|-------|
+| matches(str) | true if the whole `str` matches     |       |
+| find(str)    | find first match in `str` or null   | (1)   |
+| findAll(str) | find all matches in `str` as [List] | (1)   |
+
+(1)
+:: See `RegexMatch` class description below
+
+# RegexMatch
+
+| name  | description                               | notes |
+|-------|-------------------------------------------|-------|
+| range | the [Range] of the match in source string |       |
+| value | the value that matches                    |       |
+| [n]   | [List] of group matches                   | (1)   |
+
+(1)
+:: the [0] element is always value, [1] is group 1 match of any, etc.
+
+[List]: List.md
+
+[Range]: Range.md
+

docs/RingBuffer.md

@@ -0,0 +1,52 @@
+# RingBuffer
+
+This is a fixed size buffer that allow to store N last elements with _O(1)_ effectiveness (no data shifting).
+
+Here is the sample:
+
+    val r = RingBuffer(3)
+    assert( r is RingBuffer )
+    assertEquals(0, r.size)
+    assertEquals(3, r.capacity)
+    
+    r += 10
+    assertEquals(1, r.size)
+    assertEquals(10, r.first)
+    
+    r += 20
+    assertEquals(2, r.size)
+    assertEquals( [10, 20], r.toList() )
+    
+    r += 30
+    assertEquals(3, r.size)
+    assertEquals( [10, 20, 30], r.toList() )
+    
+    // now first value is lost:
+    r += 40
+    assertEquals(3, r.size)
+    assertEquals( [20, 30, 40], r.toList() )
+    assertEquals(3, r.capacity)
+
+    >>> void
+
+Ring buffer implements [Iterable], so any of its methods are available for `RingBuffer`, e.g. `first`, `last`, `toList`,
+`take`, `drop`, `takelast`, `dropLast`, etc.
+
+## Constructor
+
+    RinbBuffer(capacity: Int)
+
+## Instance methods
+
+| method      | description            | remarks |
+|-------------|------------------------|---------|
+| capacity    | max size of the buffer |         |
+| size        | current size           | (1)     |
+| operator += | add new item           | (1)     |
+| add(item)   | add new item           | (1)     |
+| iterator()  | return iterator        | (1)     |
+
+(1)
+: Ringbuffer is not threadsafe, protect it with a mutex to avoid RC where necessary.
+
+[Iterable]: Iterable.md

docs/Set.md

@@ -0,0 +1,94 @@
+# List built-in class
+
+Mutable set of any objects: a group of different objects, no repetitions.
+Sets are not ordered, order of appearance does not matter.
+
+    val set = Set(1,2,3, "foo")
+    assert( 1 in set )
+    assert( "foo" in set)
+    assert( "bar" !in set)
+    >>> void
+
+## Set is collection and therefore [Iterable]:
+
+    assert( Set(1,2) is Set)
+    assert( Set(1,2) is Iterable)
+    assert( Set(1,2) is Collection)
+    >>> void
+
+So it supports all methods from [Iterable]; set is not, though, an [Array] and has
+no indexing. Use [set.toList] as needed.
+
+## Set operations
+
+    // Union
+    assertEquals( Set(1,2,3,4), Set(3, 1) + Set(2, 4))
+
+    // intersection
+    assertEquals( Set(1,4), Set(3, 1, 4).intersect(Set(2, 4, 1)) )
+    // or simple
+    assertEquals( Set(1,4), Set(3, 1, 4) * Set(2, 4, 1) )
+
+    // To find collection elements not present in another collection, use the 
+    // subtract() or `-`:
+    assertEquals( Set( 1, 2), Set(1, 2, 4, 3) - Set(3, 4))
+
+    >>> void
+
+## Adding elements
+
+    var s = Set()
+    s += 1
+    assertEquals( Set(1), s)
+    
+    s += [3, 3, 4]
+    assertEquals( Set(3, 4, 1), s)
+    >>> void
+
+## Removing elements
+
+List is mutable, so it is possible to remove its contents. To remove a single element
+by index use:
+
+    var s = Set(1,2,3)
+    s.remove(2)
+    assertEquals( s, Set(1,3) )
+
+    s = Set(1,2,3)
+    s.remove(2,1)
+    assertEquals( s, Set(3) )
+    >>> void
+
+Note that `remove` returns true if at least one element was actually removed and false
+if the set has not been changed.
+
+## Comparisons and inclusion
+
+Sets are only equal when contains exactly same elements, order, as was said, is not significant:
+
+    assert( Set(1, 2) == Set(2, 1) )
+    assert( Set(1, 2, 2) == Set(2, 1) )
+    assert( Set(1, 3) != Set(2, 1) )
+    assert( 1 in Set(5,1))
+    assert( 10 !in Set(5,1))
+    >>> void
+
+## Members
+
+| name                | meaning                              | type  |
+|---------------------|--------------------------------------|-------|
+| `size`              | current size                         | Int   |
+| `+=`                | add one or more elements             | Any   |
+| `+`, `union`         | union sets                           | Any   |
+| `-`, `subtract`     | subtract sets                        | Any   |
+| `*`, `intersect`    | subtract sets                        | Any   |
+| `remove(items...)`  | remove one or more items             | Range |
+| `contains(element)` | check the element is in the list (1) |       |
+
+(1)
+: optimized implementation that override `Iterable` one
+
+Also, it inherits methods from [Iterable].
+
+
+[Range]: Range.md

docs/advanced_topics.md

@@ -1,5 +1,7 @@
 # Advanced topics
 
+__See also:__ [parallelism].
+
 ## Closures/scopes isolation
 
 Each block has own scope, in which it can safely use closures and override
@@ -87,3 +89,72 @@ Lambda functions remember their scopes, so it will work the same as previous:
     println(c)
     >> 1
     >> void
+
+# Elements of functional programming
+
+With ellipsis and splats you can create partial functions, manipulate
+arguments list in almost arbitrary ways. For example:
+
+    // Swap first and last arguments for call
+
+    fun swap_args(first, others..., last, f) { 
+        f(last, ...others, first) 
+    }
+
+    fun glue(args...) {
+        var result = ""
+        for( a in args ) result += a
+    }
+
+    assertEquals( 
+        "4231", 
+        swap_args( 1, 2, 3, 4, glue)
+    )
+    >>> void
+
+# Annotations
+
+Annotation in Lyng resembles these proposed for Javascript. Annotation is just regular functions that, if used as annotation, are called when defining a function, var, val or class. 
+
+## Function annotation
+
+When used without params, annotation calls a function with two arguments: actual function name and callable function body. Function annotation __must return callable for the function__, either what it received as a second argument (most often), or something else. Annotation name convention is upper scaled: 
+
+    var annotated = false
+    
+    // this is annotation function:
+    fun Special(name, body) {
+        assertEquals("foo", name)
+        annotated = true
+        { body(it) + 100 }
+    }
+
+    @Special
+    fun foo(value) { value + 1 }
+
+    assert(annotated)
+    assertEquals(111, foo( 10 ))
+    >>> void
+
+Function annotation can have more args specified at call time. There arguments must follow two mandatory ones (name and body). Use default values in order to allow parameterless annotation to be used simultaneously.
+
+    val registered = Map()
+
+    // it is recommended to provide defaults for extra parameters:
+    fun Registered(name, body, overrideName = null) {
+        registered[ overrideName ?: name ] = body
+        body
+    }
+
+    // witout parameters is Ok as we provided default value
+    @Registered
+    fun foo() { "called foo" }
+
+    @Registered("bar") 
+    fun foo2() { "called foo2" }
+
+    assertEquals(registered["foo"](), "called foo")
+    assertEquals(registered["bar"](), "called foo2")
+    >>> void
+
+[parallelism]: parallelism.md

docs/class_reference.md

@@ -1,24 +0,0 @@
-# Classes
-
-## Declaring
-
-    class Foo1
-    class Foo2() // same, empty constructor
-    class Foo3() { // full
-    }
-    class Foo4 { // Only body
-    }
-
-```
-class_declaration = ["abstract",] "class" [, constructor] [, body]
-constructor = "(", [field [, field]] ")
-field = [visibility ,] [access ,] name [, typedecl]
-body = [visibility] ("var", vardecl) | ("val", vardecl) | ("fun", fundecl)
-visibility = "private" | "protected" | "internal"
-```
-
-### Abstract classes
-
-Contain one pr more abstract methods which must be implemented; though they
-can have constructors, the instances of the abstract classes could not be
-created independently

docs/declaring_arguments.md

@@ -5,7 +5,7 @@ lambdas and class declarations.
 
 ## Regular
 
-## default values
+## Default values
 
 Default parameters should not be mixed with mandatory ones:
 
@@ -83,7 +83,7 @@ or whatever implementing [Iterable], is called _splats_. Here is how we use it:
     }
     val array = [1,2,3]
     testSplat("start", ...array, "end")
-    >>> ["start", 1, 2, 3, "end"]
+    >>> [start,1,2,3,end]
     >>> void
 
 There could be any number of splats at any positions. You can splat any other [Iterable] type:
@@ -93,8 +93,63 @@ There could be any number of splats at any positions. You can splat any other [I
     }
     val range = 1..3
     testSplat("start", ...range, "end")
-    >>> ["start", 1, 2, 3, "end"]
+    >>> [start,1,2,3,end]
     >>> void
 
+## Named arguments in calls
+
+Lyng supports named arguments at call sites using colon syntax `name: value`:
+
+```lyng
+    fun test(a="foo", b="bar", c="bazz") { [a, b, c] }
+
+    assertEquals(["foo", "b", "bazz"], test(b: "b"))
+    assertEquals(["a", "bar", "c"], test("a", c: "c"))
+```
+
+Rules:
+
+- Named arguments must follow positional arguments. After the first named argument, no positional arguments may appear inside the parentheses.
+- The only exception is the syntactic trailing block after the call: `f(args) { ... }`. This block is outside the parentheses and is handled specially (see below).
+- A named argument cannot reassign a parameter already set positionally.
+- If the last parameter has already been assigned by a named argument (or named splat), a trailing block is not allowed and results in an error.
+
+Why `:` and not `=` at call sites? In Lyng, `=` is an expression (assignment), so we use `:` to avoid ambiguity. Declarations continue to use `:` for types, while call sites use `as` / `as?` for type operations.
+
+## Named splats (map splats)
+
+Splat (`...`) of a Map provides named arguments to the call. Only string keys are allowed:
+
+```lyng
+    fun test(a="a", b="b", c="c", d="d") { [a, b, c, d] }
+    val r = test("A?", ...Map("d" => "D!", "b" => "B!"))
+    assertEquals(["A?","B!","c","D!"], r)
+```
+
+The same with a map literal is often more concise. Define the literal, then splat the variable:
+
+    fun test(a="a", b="b", c="c", d="d") { [a, b, c, d] }
+    val patch = { d: "D!", b: "B!" }
+    val r = test("A?", ...patch)
+    assertEquals(["A?","B!","c","D!"], r)
+    >>> void
+
+Constraints:
+
+- Map splat keys must be strings; otherwise, a clean error is thrown.
+- Named splats cannot duplicate parameters already assigned (by positional or named arguments).
+- Named splats must follow all positional arguments and positional splats.
+- Ellipsis parameters (variadic) remain positional-only and cannot be assigned by name.
+
+## Trailing-lambda rule interaction
+
+If a call is immediately followed by a block `{ ... }`, it is treated as an extra last argument and bound to the last parameter. However, if the last parameter is already assigned by a named argument or a named splat, using a trailing block is an error:
+
+```lyng
+    fun f(x, onDone) { onDone(x) }
+    f(x: 1) { 42 }   // ERROR
+    f(1) { 42 }      // OK
+```
+    
 
 [tutorial]: tutorial.md

docs/development/String.md

@@ -0,0 +1,28 @@
+[//]: # (excludeFromIndex)
+
+# String
+
+# This document is for developer notes only
+
+--------------------------
+
+
+## Interpolation proposal
+
+"""no $iterpolation"""
+    
+    val inpterpolation1 = "foo"
+    "${interpolation1}"
+    >>> "foo"
+
+"$interpolation2"
+"no $$ interpolatino"
+
+
+## Regexp vs div / ?
+
+```EBNF
+regex_literal = "/", { regchar }, "/", [ flag ]
+foag = "i" | "n"....
+regchar = x`x`
+```

docs/development/including_modules.md

@@ -1,5 +1,7 @@
 # Modules inclusion
 
+[//]: # (excludeFromIndex)
+
 Module is, at the low level, a statement that modifies a given context by adding
 here local and exported symbols, performing some tasks and even returning some value
 we don't need for now.

docs/development/scope_resolution.md

@@ -0,0 +1,15 @@
+[//]: # (excludeFromIndex)
+
+
+Provide:
+
+
+    fun outer(a1)
+        // a1 is caller.a1:arg
+        val a1_local = a1 + 1
+        // we return lambda:
+        { it ->
+            // a1_local
+            a1_lcoal + it
+        }
+    }

docs/embedding.md

@@ -0,0 +1,236 @@
+# Embedding Lyng in your Kotlin project
+
+Lyng is a tiny, embeddable, Kotlin‑first scripting language. This page shows, step by step, how to:
+
+- add Lyng to your build
+- create a runtime and execute scripts
+- define functions and variables from Kotlin
+- read variable values back in Kotlin
+- call Lyng functions from Kotlin
+- create your own packages and import them in Lyng
+
+All snippets below use idiomatic Kotlin and rely on Lyng public APIs. They work on JVM and other Kotlin Multiplatform targets supported by `lynglib`.
+
+Note: all Lyng APIs shown are `suspend`, because script evaluation is coroutine‑friendly and can suspend.
+
+### 1) Add Lyng to your build
+
+Add the repository where you publish Lyng artifacts and the dependency on the core library `lynglib`.
+
+Gradle Kotlin DSL (build.gradle.kts):
+
+```kotlin
+repositories {
+    // Your standard repos
+    mavenCentral()
+
+    // If you publish to your own Maven (example: Gitea packages). Adjust URL/token as needed.
+    maven(url = uri("https://gitea.sergeych.net/api/packages/SergeychWorks/maven"))
+}
+
+dependencies {
+    // Multiplatform: place in appropriate source set if needed
+    implementation("net.sergeych:lynglib:1.0.0-SNAPSHOT")
+}
+```
+
+If you use Kotlin Multiplatform, add the dependency in the `commonMain` source set (and platform‑specific sets if you need platform APIs).
+
+### 2) Create a runtime (Scope) and execute scripts
+
+The easiest way to get a ready‑to‑use scope with standard packages is via `Script.newScope()`.
+
+```kotlin
+fun main() = kotlinx.coroutines.runBlocking {
+    val scope = Script.newScope() // suspends on first init
+
+    // Evaluate a one‑liner
+    val result = scope.eval("1 + 2 * 3")
+    println("Lyng result: $result") // ObjReal/ObjInt etc.
+}
+```
+
+You can also pre‑compile a script and execute it multiple times:
+
+```kotlin
+val script = Compiler.compile("""
+    // any Lyng code
+    val x = 40 + 2
+    x
+""")
+
+val run1 = script.execute(scope)
+val run2 = script.execute(scope)
+```
+
+`Scope.eval("...")` is a shortcut that compiles and executes on the given scope.
+
+### 3) Define variables from Kotlin
+
+To expose data to Lyng, add constants (read‑only) or mutable variables to the scope. All values in Lyng are `Obj` instances; the core types live in `net.sergeych.lyng.obj`.
+
+```kotlin
+// Read‑only constant
+scope.addConst("pi", ObjReal(3.14159))
+
+// Mutable variable: create or update
+scope.addOrUpdateItem("counter", ObjInt(0))
+
+// Use it from Lyng
+scope.eval("counter = counter + 1")
+```
+
+Tip: Lyng values can be converted back to Kotlin with `toKotlin(scope)`:
+
+```kotlin
+val current = (scope.eval("counter")).toKotlin(scope) // Any? (e.g., Int/Double/String/List)
+```
+
+### 4) Add Kotlin‑backed functions
+
+Use `Scope.addFn`/`addVoidFn` to register functions implemented in Kotlin. Inside the lambda, use `this.args` to access arguments and return an `Obj`.
+
+```kotlin
+// A function returning value
+scope.addFn<ObjInt>("inc") {
+    val x = args.firstAndOnly() as ObjInt
+    ObjInt(x.value + 1)
+}
+
+// A void function (returns Lyng Void)
+scope.addVoidFn("log") {
+    val items = args.list // List<Obj>
+    println(items.joinToString(" ") { it.toString(this).value })
+}
+
+// Call them from Lyng
+scope.eval("val y = inc(41); log('Answer:', y)")
+```
+
+You can register multiple names (aliases) at once: `addFn<ObjInt>("inc", "increment") { ... }`.
+
+### 5) Read variable values back in Kotlin
+
+The simplest approach: evaluate an expression that yields the value and convert it.
+
+```kotlin
+val kotlinAnswer = scope.eval("(1 + 2) * 3").toKotlin(scope) // -> 9 (Int)
+
+// After scripts manipulate your vars:
+scope.addOrUpdateItem("name", ObjString("Lyng"))
+scope.eval("name = name + ' rocks!'")
+val kotlinName = scope.eval("name").toKotlin(scope) // -> "Lyng rocks!"
+```
+
+Advanced: you can also grab a variable record directly via `scope.get(name)` and work with its `Obj` value, but evaluating `"name"` is often clearer and enforces Lyng semantics consistently.
+
+### 6) Execute scripts with parameters; call Lyng functions from Kotlin
+
+There are two convenient patterns.
+
+1) Evaluate a Lyng call expression directly:
+
+```kotlin
+// Suppose Lyng defines: fun add(a, b) = a + b
+scope.eval("fun add(a, b) = a + b")
+
+val sum = scope.eval("add(20, 22)").toKotlin(scope) // -> 42
+```
+
+2) Call a Lyng function by name via a prepared call scope:
+
+```kotlin
+// Ensure the function exists in the scope
+scope.eval("fun add(a, b) = a + b")
+
+// Look up the function object
+val addFn = scope.get("add")!!.value as Statement
+
+// Create a child scope with arguments (as Lyng Objs)
+val callScope = scope.createChildScope(
+    args = Arguments(listOf(ObjInt(20), ObjInt(22)))
+)
+
+val resultObj = addFn.execute(callScope)
+val result = resultObj.toKotlin(scope) // -> 42
+```
+
+If you need to pass complex data (lists, maps), construct the corresponding Lyng `Obj` types (`ObjList`, `ObjMap`, etc.) and pass them in `Arguments`.
+
+### 7) Create your own packages and import them in Lyng
+
+Lyng supports packages that are imported from scripts. You can register packages programmatically via `ImportManager` or by providing source texts that declare `package ...`.
+
+Key concepts:
+
+- `ImportManager` holds package registrations and lazily builds `ModuleScope`s when first imported.
+- Every `Scope` has `currentImportProvider` and (if it’s an `ImportManager`) a convenience `importManager` to register packages.
+
+Register a Kotlin‑built package:
+
+```kotlin
+val scope = Script.newScope()
+
+// Access the import manager behind this scope
+val im: ImportManager = scope.importManager
+
+// Register a package "my.tools"
+im.addPackage("my.tools") { module: ModuleScope ->
+    // Expose symbols inside the module scope
+    module.addConst("version", ObjString("1.0"))
+    module.addFn<ObjInt>("triple") {
+        val x = args.firstAndOnly() as ObjInt
+        ObjInt(x.value * 3)
+    }
+}
+
+// Use it from Lyng
+scope.eval("""
+    import my.tools.*
+    val v = triple(14)
+""")
+val v = scope.eval("v").toKotlin(scope) // -> 42
+```
+
+Register a package from Lyng source text:
+
+```kotlin
+val pkgText = """
+    package math.extra
+
+    fun sqr(x) = x * x
+""".trimIndent()
+
+scope.importManager.addTextPackages(pkgText)
+
+scope.eval("""
+    import math.extra.*
+    val s = sqr(12)
+""")
+val s = scope.eval("s").toKotlin(scope) // -> 144
+```
+
+You can also register from parsed `Source` instances via `addSourcePackages(source)`.
+
+### 8) Executing from files, security, and isolation
+
+- To run code from a file, read it and pass to `scope.eval(text)` or compile with `Compiler.compile(Source(fileName, text))`.
+- `ImportManager` takes an optional `SecurityManager` if you need to restrict what packages or operations are available. By default, `Script.defaultImportManager` allows everything suitable for embedded use; clamp it down in sandboxed environments.
+- For isolation, create fresh modules/scopes via `Scope.new()` or `Script.newScope()` when you need a clean environment per request.
+
+```kotlin
+// Fresh module based on the default manager, without the standard prelude
+val isolated = net.sergeych.lyng.Scope.new()
+```
+
+### 9) Tips and troubleshooting
+
+- All values that cross the boundary must be Lyng `Obj` instances. Convert Kotlin values explicitly (e.g., `ObjInt`, `ObjReal`, `ObjString`).
+- Use `toKotlin(scope)` to get Kotlin values back. Collections convert to Kotlin collections recursively.
+- Most public API in Lyng is suspendable. If you are not already in a coroutine, wrap calls in `runBlocking { ... }` on the JVM for quick tests.
+- When registering packages, names must be unique. Register before you compile/evaluate scripts that import them.
+- To debug scope content, `scope.toString()` and `scope.trace()` can help during development.
+
+---
+
+That’s it. You now have Lyng embedded in your Kotlin app: you can expose your app’s API, evaluate user scripts, and organize your own packages to import from Lyng code.

docs/exceptions_handling.md

@@ -81,6 +81,22 @@ to catch all exceptions to, then you can write it even shorter:
 You can even check the type of the `it` and create more convenient and sophisticated processing logic. Such approach is
 used, for example, in Scala.
 
+## finally block
+
+If `finally` block present, it will be executed after body (until first exception)
+and catch block, if any will match. finally statement is executed even if the
+exception will be thrown and not caught locally. It does not alter try/catch block result:
+
+    try {
+    }
+    finally {
+        println("called finally")
+    }
+    >>> called finally
+    >>> void
+
+- and yes, there could be try-finally block, no catching, but perform some guaranteed cleanup.
+
 # Conveying data with exceptions
 
 The simplest way is to provide exception string and `Exception` class:
@@ -106,6 +122,32 @@ This way, in turn, can also be shortened, as it is overly popular:
 The trick, though, works with strings only, and always provide `Exception` instances, which is good for debugging but
 most often not enough.
 
+# Exception class
+
+Serializable class that conveys information about the exception. Important members and methods are:
+
+| name              | description                                            |
+|-------------------|--------------------------------------------------------|
+| message           | String message                                         |
+| stackTrace        | lyng stack trace, list of `StackTraceEntry`, see below |
+| printStackTrace() | format and print stack trace using println()           |
+
+## StackTraceEntry
+
+A simple structire that stores single entry in Lyng stack, it is created automatically on exception creation:
+
+```kotlin
+class StackTraceEntry(
+    val sourceName: String,
+    val line: Int,
+    val column: Int,
+    val sourceString: String
+)
+```
+
+- `sourceString` is a line extracted from sources. Note that it _is serialized and printed_, so if you want to conceal it, catch all exceptions and filter out sensitive information.
+
+
 # Custom error classes
 
 _this functionality is not yet released_
@@ -115,7 +157,7 @@ _this functionality is not yet released_
 | class                      | notes                                                 |
 |----------------------------|-------------------------------------------------------|
 | Exception                  | root of al throwable objects                          |
-| NullPointerException       |                                                       |
+| NullReferenceException     |                                                       |
 | AssertionFailedException   |                                                       | 
 | ClassCastException         |                                                       |
 | IndexOutOfBoundsException  |                                                       |

docs/math.md

@@ -9,17 +9,37 @@ Same as in C++.
 | **Highest**<br>0 | power, not, calls, indexing, dot,... |
 |        1         | `%` `*` `/`                          |
 |        2         | `+` `-`                              |
-|        3         | bit shifts (NI)                      |
+|        3         | bit shifts `<<` `>>`                 |
 |        4         | `<=>` (1)                            |
 |        5         | `<=` `>=` `<` `>`                    |
 |        6         | `==` `!=`                            |
-|        7         | bitwise and `&` (NI)                 |
+|        7         | bitwise and `&`                      |
-|        9         | bitwise or `\|` (NI)                 |
+|        8         | bitwise xor `^`                      |
+|        9         | bitwise or `\|`                      |
 |        10        | `&&`                                 |
 |  11<br/>lowest   | `\|\|`                               |
 
-(NI)
+Bitwise operators
-: not yet implemented.
+: available only for `Int` values. For mixed `Int`/`Real` numeric expressions, bitwise operators are not defined.
+
+Bitwise NOT `~x`
+: unary operator that inverts all bits of a 64‑bit signed integer (`Int`). It follows two's‑complement rules, so
+  `~x` is numerically equal to `-(x + 1)`. Examples: `~0 == -1`, `~1 == -2`, `~(-1) == 0`.
+
+Examples:
+
+```
+5 & 3    // -> 1
+5 | 3    // -> 7
+5 ^ 3    // -> 6
+~0       // -> -1
+1 << 3   // -> 8
+8 >> 3   // -> 1
+```
+
+Notes:
+- Shifts operate on 64-bit signed integers (`Int` is 64-bit). Right shift `>>` is arithmetic (sign-propagating).
+- Shift count is masked to the range 0..63, similar to the JVM/Kotlin behavior (e.g., `1 << 65` equals `1 << 1`).
 
 (1)
 : Shuttle operator: `a <=> b` returns 0 if a == b, negative Int if a < b and positive Int otherwise. It is necessary to

docs/parallelism.md

@@ -0,0 +1,221 @@
+# Parallelism in Lyng
+
+Lyng is built to me multithreaded where possible (e.g. all targets byt JS and wasmJS as for now)
+and cooperatively parallel (coroutine based) everywhere.
+
+In Lyng, every function, every lambda are _coroutines_. It means, you can have as many of these as you want without risking running out of memory on threads stack, or get too many threads.
+
+Depending on the platform, these coroutines may be executed on different CPU and cores, too, truly in parallel. Where not, like Javascript browser, they are still executed cooperatively. You should not care about the platform capabilities, just call `launch`:
+
+    // track coroutine call: 
+    var xIsCalled = false
+
+    // launch coroutine in parallel
+    val x = launch { 
+        // wait 10ms to let main code to be executed
+        delay(10)
+        // now set the flag
+        xIsCalled = true
+        // and return something useful:
+        "ok"
+    }
+    // corouine is launhed, but not yet executed
+    // due to delay call:
+    assert(!xIsCalled)
+    
+    // now we wait for it to be executed:
+    assertEquals( x.await(), "ok")
+
+    // now glag should be set:
+    assert(xIsCalled)
+    >>> void
+
+This example shows how to launch a coroutine with `launch` which returns [Deferred] instance, the latter have ways to await for the coroutine completion and retrieve possible result.
+
+Launch has the only argument which should be a callable (lambda usually) that is run in parallel (or cooperatively in parallel), and return anything as the result.
+
+## Synchronization: Mutex
+
+Suppose we have a resource, that could be used concurrently, a counter in our case. If we won't protect it, concurrent usage cause RC, Race Condition, providing wrong result:
+
+    var counter = 0
+    
+    (1..50).map { 
+        launch {
+            // slow increment:
+            val c = counter
+            delay(100)
+            counter = c + 1
+        }
+    }.forEach { it.await() }
+    assert(counter < 50) { "counter is "+counter }
+    >>> void
+
+The obviously wrong result is not 4, as all coroutines capture the counter value, which is 1, then sleep for 5ms, then save 1 + 1 as result. May some coroutines will pass, so it will be 1 or 2, most likely.
+
+Using [Mutex] makes it all working:
+
+    var counter = 0
+    val mutex = Mutex()
+    
+    (1..4).map { 
+        launch {
+            // slow increment:
+            mutex.withLock {
+                val c = counter
+                delay(10)
+                counter = c + 1
+            }
+        }
+    }.forEach { it.await() }
+    assertEquals(4, counter)
+    >>> void
+
+now everything works as expected: `mutex.withLock` makes them all be executed in sequence, not in parallel.
+
+
+## Completable deferred
+
+Sometimes it is convenient to manually set completion status of some deferred result. This is when [CompletableDeferred] is used:
+
+    // this variable will be completed later:
+    val done = CompletableDeferred()
+    
+    // complete it ater delay
+    launch { 
+        delay(10)
+        // complete it setting the result:
+        done.complete("ok")
+    }
+    
+    // now it is still not completed: coroutine is delayed
+    // (ot not started on sinthe-threaded platforms):
+    assert(!done.isCompleted)
+    assert(done.isActive)
+
+    // then we can just await it as any other deferred:
+    assertEquals( done.await(), "ok")
+    // and as any other deferred it is now complete:
+    assert(done.isCompleted)
+
+## True parallelism
+
+Cooperative, coroutine-based parallelism is automatically available on all platforms. Depending on the platform, though, the coroutines could be dispatched also in different threads; where there are multiple cores and/or CPU available, it means the coroutines could be exuted truly in parallel, unless [Mutex] is used:
+
+| platofrm   | multithreaded |
+|------------|---------------|
+| JVM        | yes           |
+| Android    | yes           |
+| Javascript | NO            |
+| wasmJS     | NO            |
+| IOS        | yes           |
+| MacOSX     | yes           |
+| Linux      | yes           |
+| Windows    | yes           |
+
+So it is important to always use [Mutex] where concurrent execution could be a problem (so called Race Conditions, or RC).
+
+## Yield
+
+When the coroutine is executed, on the single-threaded environment all other coroutines are suspended until active one will wait for something. Sometimes, it is undesirable; the coroutine may perform long calculations or some other CPU consuming task. The solution is to call `yield()` periodically. Unlike `delay()`, yield does not pauses the coroutine for some specified time, but it just makes all other coroutines to be executed. In other word, yield interrupts current coroutines and out it to the end of the dispatcher list of active coroutines. It is especially important on Javascript and wasmJS targets as otherwise UI thread could be blocked. 
+
+Usage example:
+
+    fun someLongTask() { // ...
+        do {
+            // execute step
+            if( done ) break
+            yield()
+        } while(true)
+    }
+
+# Data exchange for coroutines
+
+## Flow
+
+Flow is an async cold sequence; it is named after kotlin's Flow as it resembles it closely. The cold means the flow is only evaluated when iterated (collected, in Kotlin terms), before it is inactive. Sequence means that it is potentially unlimited, as in our example of glorious Fibonacci number generator:
+
+    // Fibonacch numbers flow! 
+    val f = flow {
+        println("Starting generator")
+        var n1 = 0
+        var n2 = 1
+        emit(n1)
+        emit(n2)
+        while(true) {
+            val n = n1 + n2
+            emit(n)
+            n1 = n2
+            n2 = n
+        }
+    }
+    val correctFibs = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765]
+    println("Generation starts")
+    assertEquals( correctFibs, f.take(correctFibs.size))
+    >>> Generation starts
+    >>> Starting generator
+    >>> void
+
+Great: the generator is not executed until collected bu the `f.take()` call, which picks specified number of elements from the flow, can cancel it.
+
+Important difference from the channels or like, every time you collect the flow, you collect it anew:
+
+    var isStarted = false
+    val f = flow {
+            emit("start")
+            isStarted = true
+            (1..4).forEach { emit(it) }
+    }
+    // flow is not yet started, e.g. not got execited, 
+    // that is called 'cold':
+    assertEquals( false, isStarted )
+
+    // let's collect flow:
+    val result = []
+    for( x in f ) result += x
+    println(result)
+
+    assertEquals( true, isStarted)
+
+    // let's collect it once again, it should be the same:
+    println(f.toList())
+
+    // and again:
+    assertEquals( result, f.toList() )
+
+    >>> [start,1,2,3,4]
+    >>> [start,1,2,3,4]
+    >>> void
+
+Notice that flow's lambda is not called until actual collection is started. Cold flows are
+better in terms of resource consumption.
+
+Flows allow easy transforming of any [Iterable]. See how the standard Lyng library functions use it:
+
+    fun Iterable.filter(predicate) {
+        val list = this
+        flow {
+            for( item in list ) {
+                if( predicate(item) ) {
+                    emit(item)
+                }
+            }
+        }
+    }
+
+
+[Iterable]: Iterable.md
+
+## Scope frame pooling (JVM)
+
+Lyng includes an optional optimization for function/method calls on JVM: scope frame pooling, toggled by the runtime flag `PerfFlags.SCOPE_POOL`.
+
+- Default: `SCOPE_POOL` is OFF on JVM.
+- Rationale: the current `ScopePool` implementation is not thread‑safe. Lyng targets multi‑threaded execution on most platforms, therefore we keep pooling disabled by default until a thread‑safe design is introduced.
+- When safe to enable: single‑threaded runs (e.g., micro‑benchmarks or scripts executed on a single worker) where no scopes are shared across threads.
+- How to toggle at runtime (Kotlin/JVM tests):
+  - `PerfFlags.SCOPE_POOL = true` to enable.
+  - `PerfFlags.SCOPE_POOL = false` to disable.
+- Expected effect (from our JVM micro‑benchmarks): in deep call loops, enabling pooling reduced total time by about 1.38× in a dedicated pooling benchmark; mileage may vary depending on workload.
+
+Future work: introduce thread‑safe pooling (e.g., per‑thread pools or confinement strategies) before considering enabling it by default in multi‑threaded environments.

docs/perf_guide.md

@@ -0,0 +1,622 @@
+
+This document explains how to enable and measure the performance optimizations added to the Lyng interpreter. The focus is JVM‑first with safe, flag‑guarded rollouts and quick A/B testing. Other targets (JS/Wasm/Native) keep conservative defaults until validated.
+
+[//]: # (excludeFromIndex)
+
+## Overview
+
+Optimizations are controlled by runtime‑mutable flags in `net.sergeych.lyng.PerfFlags`, initialized from platform‑specific static defaults `net.sergeych.lyng.PerfDefaults` (KMP `expect/actual`).
+
+- JVM/Android defaults are aggressive (e.g. `RVAL_FASTPATH=true`).
+- Non‑JVM defaults are conservative (e.g. `RVAL_FASTPATH=false`).
+
+All flags are `var` and can be flipped at runtime (e.g., from tests or host apps) for A/B comparisons.
+
+### Workload presets (JVM‑first)
+
+To simplify switching between recommended flag sets for different workloads, use `net.sergeych.lyng.PerfProfiles`:
+
+```
+val snap = PerfProfiles.apply(PerfProfiles.Preset.BENCH)  // or BASELINE / BOOKS
+// ... run workload ...
+PerfProfiles.restore(snap)  // restore previous flags
+```
+
+- BASELINE: restores platform defaults from `PerfDefaults` (good rollback point).
+- BENCH: expression‑heavy micro‑bench focus (aggressive R‑value and PIC optimizations on JVM).
+- BOOKS: documentation workloads (prefers simpler paths; disables some PIC/arg builder features shown neutral/negative for this load in A/B).
+
+## Key flags
+
+- `LOCAL_SLOT_PIC` — Runtime cache in `LocalVarRef` to avoid repeated name→slot lookups per frame (ON JVM default).
+- `EMIT_FAST_LOCAL_REFS` — Compiler emits `FastLocalVarRef` for identifiers known to be locals/params (ON JVM default).
+- `ARG_BUILDER` — Efficient argument building: small‑arity no‑alloc and pooled builder on JVM (ON JVM default).
+- `ARG_SMALL_ARITY_12` — Extends small‑arity no‑alloc call paths from 0–8 to 0–12 arguments (JVM‑first exploration; OFF by default). Use for codebases with many 9–12 arg calls; A/B before enabling.
+- `SKIP_ARGS_ON_NULL_RECEIVER` — Early return on optional‑null receivers before building args (semantics‑compatible). A/B only.
+- `SCOPE_POOL` — Scope frame pooling for calls (JVM, per‑thread ThreadLocal pool). ON by default on JVM; togglable at runtime.
+- `FIELD_PIC` — 2‑entry polymorphic inline cache for field reads/writes keyed by `(classId, layoutVersion)` (ON JVM default).
+- `METHOD_PIC` — 2‑entry PIC for instance method calls keyed by `(classId, layoutVersion)` (ON JVM default).
+- `FIELD_PIC_SIZE_4` — Increases Field PIC size from 2 to 4 entries (JVM-first tuning; OFF by default). Use for sites with >2 receiver shapes.
+- `METHOD_PIC_SIZE_4` — Increases Method PIC size from 2 to 4 entries (JVM-first tuning; OFF by default).
+- `PIC_ADAPTIVE_2_TO_4` — Adaptive growth of Field/Method PICs from 2→4 entries per-site when miss rate >20% over ≥256 accesses (JVM-first; OFF by default).
+- `INDEX_PIC` — Enables polymorphic inline cache for indexing (e.g., `a[i]`) and related fast paths. Defaults to follow `FIELD_PIC` on init; can be toggled independently.
+- `INDEX_PIC_SIZE_4` — Increases Index PIC size from 2 to 4 entries (JVM-first tuning). Default: ON for JVM; OFF elsewhere by default.
+- `PIC_DEBUG_COUNTERS` — Enable lightweight hit/miss counters via `PerfStats` (OFF by default).
+- `PRIMITIVE_FASTOPS` — Fast paths for `(ObjInt, ObjInt)` arithmetic/comparisons and `(ObjBool, ObjBool)` logic (ON JVM default).
+- `RVAL_FASTPATH` — Bypass `ObjRecord` in pure expression evaluation via `ObjRef.evalValue` (ON JVM default, OFF elsewhere).
+
+See `src/commonMain/kotlin/net/sergeych/lyng/PerfFlags.kt` and `PerfDefaults.*.kt` for details and platform defaults.
+
+## Where optimizations apply
+
+- Locals: `FastLocalVarRef`, `LocalVarRef` per‑frame cache (PIC).
+- Calls: small‑arity zero‑alloc paths (0–8 args; optionally 0–12 with `ARG_SMALL_ARITY_12`), pooled builder (JVM), and child frame pooling (optional).
+- Properties/methods: Field/Method PICs with receiver shape `(classId, layoutVersion)` and handle‑aware caches; configurable 2→4 entries under flags.
+- Expressions: R‑value fast paths in hot nodes (`UnaryOpRef`, `BinaryOpRef`, `ElvisRef`, logical ops, `RangeRef`, `IndexRef` read, `FieldRef` receiver eval, `ListLiteralRef` elements, `CallRef` callee, `MethodCallRef` receiver, assignment RHS).
+- Primitives: Direct boolean/int ops where safe.
+
+### Compiler constant folding (conservative)
+- The compiler folds a safe subset of literal‑only expressions at compile time to reduce runtime work:
+  - Integer arithmetic: `+ - * / %` (division/modulo only when divisor ≠ 0).
+  - Bitwise integer ops: `& ^ | << >>`.
+  - Comparisons and equality for ints/strings/chars: `== != < <= > >=`.
+  - Boolean logic for literal booleans: `|| &&` and unary `!`.
+  - String concatenation of literal strings: `"a" + "b"`.
+- Non‑literal operands or side‑effecting constructs are not folded.
+- Semantics remain unchanged; tests verify parity.
+
+## Running JVM micro‑benchmarks
+
+Each benchmark prints timings with `[DEBUG_LOG]` and includes correctness assertions to prevent dead‑code elimination.
+
+Run individual tests to avoid multiplatform matrices:
+
+```
+./gradlew :lynglib:jvmTest --tests LocalVarBenchmarkTest
+./gradlew :lynglib:jvmTest --tests CallBenchmarkTest
+./gradlew :lynglib:jvmTest --tests CallMixedArityBenchmarkTest
+./gradlew :lynglib:jvmTest --tests CallSplatBenchmarkTest
+./gradlew :lynglib:jvmTest --tests PicBenchmarkTest
+./gradlew :lynglib:jvmTest --tests PicInvalidationJvmTest
+./gradlew :lynglib:jvmTest --tests PicAdaptiveABTest
+./gradlew :lynglib:jvmTest --tests ArithmeticBenchmarkTest
+./gradlew :lynglib:jvmTest --tests ExpressionBenchmarkTest
+./gradlew :lynglib:jvmTest --tests IndexPicABTest
+./gradlew :lynglib:jvmTest --tests IndexWritePathABTest
+./gradlew :lynglib:jvmTest --tests CallPoolingBenchmarkTest
+./gradlew :lynglib:jvmTest --tests MethodPoolingBenchmarkTest
+./gradlew :lynglib:jvmTest --tests MixedBenchmarkTest
+./gradlew :lynglib:jvmTest --tests DeepPoolingStressJvmTest
+```
+
+Typical output (example):
+
+```
+[DEBUG_LOG] [BENCH] mixed-arity x200000 [ARG_BUILDER=ON]: 85.7 ms
+```
+
+Lower time is better. Run the same bench with a flag OFF vs ON to compare.
+
+### Optional JFR allocation profiling (JVM)
+
+When running end‑to‑end “book” workloads or heavier benches, you can enable JFR to capture allocation and GC details:
+
+```
+./gradlew :lynglib:jvmTest --tests BookAllocationProfileTest -Dlyng.jfr=true \
+  -Dlyng.profile.warmup=1 -Dlyng.profile.repeats=3 -Dlyng.profile.shuffle=true
+```
+
+- Dumps are saved to `lynglib/build/jfr_*.jfr` if the JVM supports Flight Recorder.
+- The test also records GC counts/time and median time/heap deltas to `lynglib/build/book_alloc_profile.txt`.
+
+## Toggling flags in tests
+
+Flags are mutable at runtime, e.g.:
+
+```kotlin
+PerfFlags.ARG_BUILDER = false
+val r1 = (Scope().eval(script) as ObjInt).value
+PerfFlags.ARG_BUILDER = true
+val r2 = (Scope().eval(script) as ObjInt).value
+```
+
+Reset flags at the end of a test to avoid impacting other tests.
+
+## PIC diagnostics (optional)
+
+Enable counters:
+
+```kotlin
+PerfFlags.PIC_DEBUG_COUNTERS = true
+PerfStats.resetAll()
+```
+
+Available counters in `PerfStats`:
+
+- Field PIC: `fieldPicHit`, `fieldPicMiss`, `fieldPicSetHit`, `fieldPicSetMiss`
+- Method PIC: `methodPicHit`, `methodPicMiss`
+- Index PIC: `indexPicHit`, `indexPicMiss`
+- Locals: `localVarPicHit`, `localVarPicMiss`, `fastLocalHit`, `fastLocalMiss`
+- Primitive ops: `primitiveFastOpsHit`
+
+Print a summary at the end of a bench/test as needed. Remember to turn counters OFF after the test.
+
+## A/B scenarios and guidance (JVM)
+
+### Adaptive PIC (fields/methods)
+- Flags: `FIELD_PIC=true`, `METHOD_PIC=true`, `FIELD_PIC_SIZE_4=false`, `METHOD_PIC_SIZE_4=false`, toggle `PIC_ADAPTIVE_2_TO_4` OFF vs ON.
+- Benchmarks: `PicBenchmarkTest`, `MixedBenchmarkTest`, `PicAdaptiveABTest`.
+- Expect wins at sites with >2 receiver shapes; counters should show fewer misses with adaptivity ON.
+
+### Index PIC and size
+- Flags: toggle `INDEX_PIC` OFF vs ON; then `INDEX_PIC_SIZE_4` OFF vs ON.
+- Benchmarks: `ExpressionBenchmarkTest` (list indexing) and `IndexPicABTest` (string/map indexing).
+- Expect wins when the same index shape recurs; counters should show higher `indexPicHit`.
+
+### Index WRITE paths (Map and List)
+- Flags: toggle `INDEX_PIC` OFF vs ON; then `INDEX_PIC_SIZE_4` OFF vs ON.
+- Benchmark: `IndexWritePathABTest` (Map[String] put, List[Int] set) — writes results to `lynglib/build/index_write_ab_results.txt`.
+- Direct fast‑paths are used on R‑value paths where safe and semantics‑preserving (e.g., optional‑chaining no‑ops on null receivers; bounds exceptions unchanged).
+
+## Guidance per flag (JVM)
+
+- Keep `RVAL_FASTPATH = true` unless debugging a suspected expression‑semantics issue.
+- Use `SCOPE_POOL = true` only for benchmarks or once pooling passes the deep stress tests and broader validation; currently OFF by default.
+- `FIELD_PIC` and `METHOD_PIC` should remain ON; they are validated with invalidation tests.
+- Consider enabling `FIELD_PIC_SIZE_4`/`METHOD_PIC_SIZE_4` for sites with 3–4 receiver shapes; measure first.
+- `PIC_ADAPTIVE_2_TO_4` is useful on polymorphic sites and may outperform fixed size 2 on mixed-shape workloads. Validate with `PicAdaptiveABTest`.
+- `INDEX_PIC` is generally beneficial on JVM; leave ON when measuring index‑heavy workloads.
+- `INDEX_PIC_SIZE_4` is ON by default on JVM as A/B showed consistent wins on String[Int] and Map[String] workloads. You can disable it by setting `PerfFlags.INDEX_PIC_SIZE_4 = false` if needed.
+- `ARG_BUILDER` should remain ON; switch OFF only to get a baseline.
+- `ARG_SMALL_ARITY_12` is experimental and OFF by default. Enable it only if your workload frequently calls functions with 9–12 arguments and A/B shows consistent wins.
+
+### Workload‑specific recommendations (JVM)
+
+- “Books”/documentation loads (BookTest): prefer simpler paths; in A/B these often benefit from the BOOKS preset (e.g., `ARG_BUILDER=false`, `SCOPE_POOL=false`, `INDEX_PIC=false`). Use `PerfProfiles.apply(PerfProfiles.Preset.BOOKS)` before the run and `restore(...)` after.
+- Expression‑heavy benches: use the BENCH preset (PICs and R‑value fast‑paths enabled, `INDEX_PIC_SIZE_4=true`).
+- Always verify with local A/B on your environment; rollback is a flag flip or applying BASELINE.
+
+## Notes on correctness & safety
+
+- Optional chaining semantics are preserved across fast paths.
+- Visibility/mutability checks are enforced even on PIC fast‑paths.
+- `frameId` is regenerated on each pooled frame borrow; stress tests verify no leakage under deep nesting/recursion.
+
+## Cross‑platform
+
+- Non‑JVM defaults keep `RVAL_FASTPATH=false` for now; other low‑risk flags may be ON.
+- Once JVM path is fully validated and measured, add lightweight benches for JS/Wasm/Native and enable flags incrementally.
+
+## Range fast iteration (experimental)
+
+- Flag: `RANGE_FAST_ITER` (default OFF).
+- When enabled and applicable, simple ascending integer ranges (`0..n`, `0..<n`) use a specialized non‑allocating iterator (`ObjFastIntRangeIterator`).
+- Benchmark: `RangeIterationBenchmarkTest` records OFF/ON timings for inclusive, exclusive, reversed, negative, and empty ranges. Semantics are preserved; non‑int or complex ranges fall back to the generic iterator.
+
+## Troubleshooting
+
+- If a benchmark shows regressions, flip related flags OFF to isolate the source (e.g., `ARG_BUILDER`, `RVAL_FASTPATH`, `FIELD_PIC`, `METHOD_PIC`).
+- Use `PIC_DEBUG_COUNTERS` to observe inline cache effectiveness.
+- Ensure tests do not accidentally keep flags ON for subsequent tests; reset after each test.
+
+
+## JVM micro-benchmark results (3× medians; OFF → ON)
+
+Date: 2025-11-10 23:04 (local)
+
+| Flag               | Benchmark/Test                              | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|--------------------|----------------------------------------------|-----------------:|----------------:|:-------:|-------|
+| ARG_BUILDER        | CallMixedArityBenchmarkTest                   |           788.02 |          668.79 |  1.18×  | Clear win on mixed arity |
+| ARG_BUILDER        | CallBenchmarkTest (simple calls)              |           423.87 |          425.47 |  1.00×  | Neutral on repeated simple calls |
+| FIELD_PIC          | PicBenchmarkTest::benchmarkFieldGetSetPic     |           113.575 |          106.017 |  1.07×  | Small but consistent win |
+| METHOD_PIC         | PicBenchmarkTest::benchmarkMethodPic          |           251.068 |          149.439 |  1.68×  | Large consistent win |
+| RVAL_FASTPATH      | ExpressionBenchmarkTest                       |           514.491 |          426.800 |  1.21×  | Consistent win in expression chains |
+| PRIMITIVE_FASTOPS  | ArithmeticBenchmarkTest (int-sum)             |           243.420 |          128.146 |  1.90×  | Big win for integer addition |
+| PRIMITIVE_FASTOPS  | ArithmeticBenchmarkTest (int-cmp)             |           210.385 |          168.534 |  1.25×  | Moderate win for comparisons |
+| SCOPE_POOL         | CallPoolingBenchmarkTest                      |           505.778 |          366.737 |  1.38×  | Single-threaded bench; per-thread ThreadLocal pool; default ON on JVM |
+
+Notes:
+- All results obtained from `[DEBUG_LOG] [BENCH]` outputs with three repeated Gradle test invocations per configuration; medians reported.
+- JVM defaults (current): `ARG_BUILDER=true`, `PRIMITIVE_FASTOPS=true`, `RVAL_FASTPATH=true`, `FIELD_PIC=true`, `METHOD_PIC=true`, `SCOPE_POOL=true` (per‑thread ThreadLocal pool), `REGEX_CACHE=true`.
+
+
+## Concurrency (multi‑core) pooling results (3× medians; OFF → ON)
+
+Date: 2025-11-10 22:56 (local)
+
+| Flag       | Benchmark/Test                      | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|------------|--------------------------------------|-----------------:|----------------:|:-------:|-------|
+| SCOPE_POOL | ConcurrencyCallBenchmarkTest (JVM)   |           521.102 |          201.374 |  2.59×  | Multithreaded workload on `Dispatchers.Default` with per‑thread ThreadLocal pool; workers=8, iters=15000/worker. |
+
+Methodology:
+- The test toggles `PerfFlags.SCOPE_POOL` within a single run and executes the same script across N worker coroutines scheduled on `Dispatchers.Default`.
+- We executed the test three times via Gradle and computed medians from the printed `[DEBUG_LOG]` timings:
+  - OFF runs (ms): 532.442 | 521.102 | 474.386 → median 521.102
+  - ON runs (ms):  218.683 | 201.374 | 198.737 → median 201.374
+- Speedup = OFF/ON.
+
+Reproduce:
+```
+./gradlew :lynglib:jvmTest --tests "ConcurrencyCallBenchmarkTest" --rerun-tasks
+```
+
+
+## Next optimization steps (JVM)
+
+Date: 2025-11-10 23:04 (local)
+
+- PICs
+  - Widen METHOD_PIC to 3–4 entries with tiny LRU; keep invalidation on layout change; re-run `PicInvalidationJvmTest`.
+  - Micro fast-path for FIELD_PIC read-then-write pairs (`x = x + 1`) to reuse the resolved slot within one step.
+- Locals and slots
+  - Pre-size `Scope` slot structures when compiler knows local/param counts; audit `EMIT_FAST_LOCAL_REFS` coverage.
+  - Re-run `LocalVarBenchmarkTest` to quantify gains.
+- RVAL_FASTPATH coverage
+  - Cover primitive `ObjList` index reads, pure receivers in `FieldRef`, and assignment RHS where safe; add micro-benches to `ExpressionBenchmarkTest`.
+- Collections and ranges
+  - Specialize `(Int..Int)` loops into tight counted loops (no intermediary objects).
+  - Add primitive-specialized `ObjList` ops (`map`, `filter`, `sum`, `contains`) under `PRIMITIVE_FASTOPS`.
+- Regex and strings
+  - Cache compiled regex for string literals at compile time; add a tiny LRU for dynamic patterns behind `REGEX_CACHE`.
+  - Add `RegexBenchmarkTest` for repeated matches.
+- JIT friendliness (Kotlin/JVM)
+  - Inline tiny helpers in hot paths, prefer arrays for internal buffers, finalize hot data structures where safe.
+
+Validation matrix
+- Always re-run: `CallBenchmarkTest`, `CallMixedArityBenchmarkTest`, `PicBenchmarkTest`, `ExpressionBenchmarkTest`, `ArithmeticBenchmarkTest`, `CallPoolingBenchmarkTest`, `DeepPoolingStressJvmTest`, `ConcurrencyCallBenchmarkTest` (3× medians when comparing).
+- Keep full `:lynglib:jvmTest` green after each change.
+
+
+
+## PIC update (4‑way METHOD_PIC) — JVM (3× medians; OFF → ON)
+
+Date: 2025-11-11 00:16 (local)
+
+| Flag      | Benchmark/Test                               | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|-----------|-----------------------------------------------|-----------------:|----------------:|:-------:|-------|
+| FIELD_PIC | PicBenchmarkTest::benchmarkFieldGetSetPic      |          207.578 |         106.481 |  1.95×  | Read→write loop; micro fast‑path groundwork present |
+| METHOD_PIC| PicBenchmarkTest::benchmarkMethodPic           |          273.478 |         182.226 |  1.50×  | 4‑way PIC with move‑to‑front (was 2‑way before) |
+
+Medians computed from three Gradle runs in this session; see `[DEBUG_LOG] [BENCH]` lines in test output.
+
+
+## Locals/slots capacity (pre‑sizing hints) — JVM (3× medians; OFF → ON)
+
+Date: 2025-11-11 13:19 (local)
+
+| Optimization            | Benchmark/Test              | OFF config                         | ON config                          | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|-------------------------|-----------------------------|------------------------------------|------------------------------------|-----------------:|----------------:|:-------:|-------|
+| Locals pre‑sizing + PIC | LocalVarBenchmarkTest       | LOCAL_SLOT_PIC=OFF, FAST_LOCAL=OFF | LOCAL_SLOT_PIC=ON, FAST_LOCAL=ON   |          472.129 |         370.871 |  1.27×  | Compiler hint `params+4`; slot pre‑size; semantics unchanged |
+
+Methodology:
+- Each configuration executed three times via `:lynglib:jvmTest --tests "…" --rerun-tasks`; medians reported.
+- Locals improvement stacks with per‑thread `SCOPE_POOL` and ARG fast paths.
+
+
+
+
+## RVAL fast paths update — JVM (IndexRef and FieldRef) [3× medians; OFF → ON]
+
+Date: 2025-11-11 13:19 (local)
+
+New micro-benchmarks have been added to quantify the latest `RVAL_FASTPATH` extensions:
+- Primitive `ObjList` index-read fast path in `IndexRef`.
+- Conservative “pure receiver” evaluation in `FieldRef` (monomorphic, immutable receiver), preserving visibility/mutability checks and optional chaining semantics.
+
+Benchmarks to run (each 3× OFF → ON):
+- `ExpressionBenchmarkTest::benchmarkListIndexReads`
+- `ExpressionBenchmarkTest::benchmarkFieldReadPureReceiver`
+
+Reproduce (3× each; collect `[DEBUG_LOG] [BENCH]` lines and compute medians):
+```
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkListIndexReads" --rerun-tasks
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkListIndexReads" --rerun-tasks
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkListIndexReads" --rerun-tasks
+
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkFieldReadPureReceiver" --rerun-tasks
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkFieldReadPureReceiver" --rerun-tasks
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkFieldReadPureReceiver" --rerun-tasks
+```
+
+Once collected, add medians and speedups to the table below:
+
+| Flag          | Benchmark/Test                                  | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|---------------|---------------------------------------------------|-----------------:|----------------:|:-------:|-------|
+| RVAL_FASTPATH | ExpressionBenchmarkTest::benchmarkListIndexReads  |           305.243 |          230.942 |  1.32×  | Fast path in `IndexRef` for `ObjList` + `ObjInt` index |
+| RVAL_FASTPATH | ExpressionBenchmarkTest::benchmarkFieldReadPureReceiver |           266.222 |          190.720 |  1.40×  | Pure-receiver evaluation in `FieldRef` (monomorphic, immutable) |
+
+Notes:
+- Both benches toggle `PerfFlags.RVAL_FASTPATH` within a single run to produce OFF and ON timings under identical conditions.
+- Correctness assertions ensure the loops are not optimized away.
+- All semantics (visibility/mutability checks, optional chaining) remain intact; fast paths only skip interim `ObjRecord` traffic when safe.
+
+
+## ARG_BUILDER — splat fast‑path (3× medians; OFF → ON)
+
+Date: 2025-11-11 13:12 (local)
+
+Environment: Gradle 8.7; JVM (JDK as configured by toolchain); single‑threaded test execution; stdout enabled.
+
+| Flag        | Benchmark/Test                    | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|-------------|-----------------------------------|-----------------:|----------------:|:-------:|-------|
+| ARG_BUILDER | CallSplatBenchmarkTest (splat)    |          613.689 |         463.593 |  1.32×  | Single‑splat fast‑path returns underlying list directly; avoids intermediate copies |
+
+Inputs (3×):
+- OFF runs (ms): 613.689 | 629.604 | 612.361 → median 613.689
+- ON runs (ms):  453.752 | 463.593 | 468.844 → median 463.593
+
+Reproduce (3×):
+```
+./gradlew :lynglib:jvmTest --tests "CallSplatBenchmarkTest" --rerun-tasks
+```
+
+
+
+## Phase A consolidation (JVM) — 3× medians updated
+
+Date: 2025-11-11 13:48 (local)
+Environment:
+- JDK: OpenJDK 20.0.2.1 (Amazon Corretto 20.0.2.1+10-FR)
+- Gradle: 8.7
+- OS/Arch: macOS 14.8.1 (aarch64)
+
+### ARG_BUILDER
+
+| Benchmark/Test                   | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|----------------------------------|-----------------:|----------------:|:-------:|-------|
+| CallMixedArityBenchmarkTest      |          866.681 |         717.439 |  1.21×  | Small-arity 0–8 fast path + builder; correctness preserved |
+| CallSplatBenchmarkTest (splat)   |          600.880 |         459.706 |  1.31×  | Single-splat fast path returns underlying list; avoids copies |
+
+Inputs (3×):
+- Mixed arity OFF: 874.088291 | 866.680959 | 858.577125 → median 866.680959
+- Mixed arity ON:  731.308625 | 706.440125 | 717.438542 → median 717.438542
+- Splat OFF: 600.268625 | 607.849416 | 600.879666 → median 600.879666
+- Splat ON:  459.706375 | 449.950166 | 461.815167 → median 459.706375
+
+### RVAL_FASTPATH (new coverage)
+
+| Benchmark/Test                                   | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|--------------------------------------------------|-----------------:|----------------:|:-------:|-------|
+| ExpressionBenchmarkTest::benchmarkListIndexReads |          299.366 |         218.812 |  1.37×  | IndexRef fast path for ObjList + ObjInt |
+| ExpressionBenchmarkTest::benchmarkFieldReadPureReceiver |          268.315 |         186.032 |  1.44×  | Pure-receiver evaluation in FieldRef (monomorphic, immutable) |
+
+Inputs (3×):
+- ListIndex OFF: 291.344 | 310.717167 | 299.365709 → median 299.365709
+- ListIndex ON:  217.795375 | 221.504166 | 218.812042 → median 218.812042
+- FieldRead OFF: 267.2775 | 274.355208 | 268.315125 → median 268.315125
+- FieldRead ON:  189.599333 | 186.031791 | 182.069167 → median 186.031791
+
+### Locals/slots capacity (precise hints)
+
+| Benchmark/Test             | OFF config                         | ON config                          | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|---------------------------|------------------------------------|------------------------------------|-----------------:|----------------:|:-------:|-------|
+| LocalVarBenchmarkTest     | LOCAL_SLOT_PIC=OFF, FAST_LOCAL=OFF | LOCAL_SLOT_PIC=ON, FAST_LOCAL=ON   |          446.018 |         347.964 |  1.28×  | Precise capacity hints + fast-locals coverage |
+
+Inputs (3×):
+- Locals OFF: 470.575041 | 441.89625 | 446.017833 → median 446.017833
+- Locals ON:  370.664208 | 345.615541 | 347.964291 → median 347.964291
+
+Methodology:
+- Each test executed three times via Gradle with stdout enabled; medians computed from `[DEBUG_LOG] [BENCH]` lines.
+- Full JVM tests and stress benches remain green in this cycle.
+
+
+
+## Phase B — List ops specialization (PRIMITIVE_FASTOPS) — 3× medians (OFF → ON)
+
+Date: 2025-11-11 13:48 (local)
+Environment:
+- JDK: OpenJDK 20.0.2.1 (Amazon Corretto 20.0.2.1+10-FR)
+- Gradle: 8.7
+- OS/Arch: macOS 14.8.1 (aarch64)
+
+| Optimization        | Benchmark/Test                          | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|---------------------|------------------------------------------|-----------------:|----------------:|:-------:|-------|
+| PRIMITIVE_FASTOPS   | ListOpsBenchmarkTest::benchmarkSumInts   |          324.805 |         144.908 |  2.24×  | ObjList.sum fast path for int lists; generic fallback preserved |
+| PRIMITIVE_FASTOPS   | ListOpsBenchmarkTest::benchmarkContainsInts |          440.414 |         415.476 |  1.06×  | ObjList.contains fast path when searching ObjInt in int list |
+
+Inputs (3×):
+- list-sum OFF: 332.863417 | 323.491625 | 324.804083 → median 324.804083
+- list-sum ON:  144.907833 | 148.870792 | 126.418542 → median 144.907833
+- list-contains OFF: 440.413709 | 440.368333 | 441.4365 → median 440.413709
+- list-contains ON:  416.465292 | 412.283291 | 415.475833 → median 415.475833
+
+Methodology:
+- Each test executed three times via Gradle; medians computed from `[DEBUG_LOG] [BENCH]` lines.
+- Changes are fully guarded by `PerfFlags.PRIMITIVE_FASTOPS`; semantics preserved (null on empty sum; generic fallback on mixed types).
+
+
+
+### Phase B — Ranges for-in lowering (PRIMITIVE_FASTOPS) — 3× medians (OFF → ON)
+
+Date: 2025-11-11 13:48 (local)
+Environment:
+- JDK: OpenJDK 20.0.2.1 (Amazon Corretto 20.0.2.1+10-FR)
+- Gradle: 8.7
+- OS/Arch: macOS 14.8.1 (aarch64)
+
+| Optimization        | Benchmark/Test                          | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|---------------------|------------------------------------------|-----------------:|----------------:|:-------:|-------|
+| PRIMITIVE_FASTOPS   | RangeBenchmarkTest::benchmarkIntRangeForIn |         1705.299 |         788.974 |  2.16×  | Tight counted loop for (Int..Int) for-in; preserves semantics |
+
+Inputs (3×):
+- range-for-in OFF: 1705.298958 | 1684.357708 | 1735.880917 → median 1705.298958
+- range-for-in ON:  794.178458 | 778.741834 | 788.973625 → median 788.973625
+
+Methodology:
+- Each configuration executed three times via Gradle; medians computed from `[DEBUG_LOG] [BENCH]` lines.
+- Lowering is guarded by `PerfFlags.PRIMITIVE_FASTOPS` and applies only when the source is an `ObjRange` with int bounds; otherwise falls back to generic iteration.
+
+
+
+## Phase B — Regex caching (REGEX_CACHE) — 3× medians (OFF → ON)
+
+Date: 2025-11-11 13:48 (local)
+Environment:
+- JDK: OpenJDK 20.0.2.1 (Amazon Corretto 20.0.2.1+10-FR)
+- Gradle: 8.7
+- OS/Arch: macOS 14.8.1 (aarch64)
+
+| Flag         | Benchmark/Test                                  | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|--------------|---------------------------------------------------|-----------------:|----------------:|:-------:|-------|
+| REGEX_CACHE  | RegexBenchmarkTest::benchmarkLiteralPatternMatches |          378.246 |         275.890 |  1.37×  | Caches compiled regex for identical literal pattern per iteration |
+| REGEX_CACHE  | RegexBenchmarkTest::benchmarkDynamicPatternMatches |          514.944 |         229.006 |  2.25×  | Two dynamic patterns alternate; cache size sufficient to retain both |
+
+Inputs (1× here; can extend to 3× on request):
+- regex-literal OFF: 378.245916; ON: 275.889541
+- regex-dynamic OFF: 514.944167; ON: 229.005834
+
+Methodology:
+- Each benchmark toggles `PerfFlags.REGEX_CACHE` inside a single test and prints `[DEBUG_LOG]` timings for OFF and ON runs under identical conditions. We recorded one set of OFF/ON timings here; we can extend to 3× medians if required for publication.
+- The cache is a tiny size-bounded map (64 entries) activated only when `PerfFlags.REGEX_CACHE` is true. Defaults remain OFF.
+
+
+
+
+## JIT tweaks (Round 1) — quick gains snapshot (locals, ranges, list ops)
+
+Date: 2025-11-11 21:05 (local)
+
+Scope: fast confirmation of overall gain using current configuration; focused on locals, ranges, and list ops. Each test prints OFF → ON timings in a single run. We executed the benches via Gradle with stdout enabled and single test fork.
+
+Environment:
+- Gradle: 8.7 (stdout enabled, maxParallelForks=1)
+- JVM: as configured by toolchain for this project
+- OS/Arch: per developer machine (unchanged from prior sections)
+
+Reproduce:
+```
+./gradlew :lynglib:jvmTest --tests LocalVarBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests RangeBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests ListOpsBenchmarkTest --rerun-tasks
+```
+
+Results (representative runs; OFF → ON):
+- Local variables — LOCAL_SLOT_PIC + EMIT_FAST_LOCAL_REFS
+  - Run 1: 468.407 ms → 367.277 ms (≈ 1.28×)
+  - Run 2: 447.031 ms → 346.126 ms (≈ 1.29×)
+- Ranges for‑in — PRIMITIVE_FASTOPS (tight counted loop for (Int..Int))
+  - 1731.780 ms → 799.023 ms (≈ 2.17×)
+- List ops — PRIMITIVE_FASTOPS
+  - sum(int list): 318.943 ms → 148.571 ms (≈ 2.15×)
+  - contains(int in int list): 440.013 ms → 412.450 ms (≈ 1.07×)
+
+Summary: All three areas improved with optimizations ON; no regressions observed in these runs. For publication‑grade stability, run each test 3× and report medians (see sections below for methodology and previous median tables).
+
+
+## Additional tweaks — verification snapshot (Index write fast‑path, List literal pre‑size, Regex LRU)
+
+Date: 2025-11-11 21:31 (local)
+
+Scope: Implemented three semantics‑neutral optimizations and verified they are green across targeted and broader JVM benches.
+
+What changed (guarded by flags where applicable):
+- RVAL_FASTPATH: Index write fast‑path
+  - `IndexRef.setAt`: direct path for `ObjList` + `ObjInt` (`list[i] = value`) mirrors the read fast‑path. Optional chaining semantics preserved; bounds exceptions propagate unchanged.
+- RVAL_FASTPATH: List literal pre‑sizing
+  - `ListLiteralRef.get`: pre‑counts element entries and uses `ArrayList` with capacity hint; for spreads of `ObjList`, uses `ensureCapacity` before bulk add. Evaluation order unchanged.
+- REGEX_CACHE: LRU‑like behavior
+  - `RegexCache`: emulates access‑order LRU within a tiny bounded map (`MAX=64`) by moving accessed entries to the tail; improves alternating‑pattern scenarios. Only active when `PerfFlags.REGEX_CACHE` is true.
+
+Reproduce quick verification (1× runs):
+```
+./gradlew :lynglib:jvmTest --tests ExpressionBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests ListOpsBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests RegexBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests PicBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests PicInvalidationJvmTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests LocalVarBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests ConcurrencyCallBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests DeepPoolingStressJvmTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests MultiThreadPoolingStressJvmTest --rerun-tasks
+```
+
+Observation: All listed tests green in this cycle; no behavioral regressions observed. For the new paths (index write, list literal), performance was neutral‑to‑positive in smoke runs; Regex benches remained positive or neutral with the LRU behavior. For publication‑grade medians, extend to 3× per test as in earlier sections.
+
+
+## Sanity matrix (JVM) — quick OFF→ON runs
+
+Date: 2025-11-11 21:59 (local)
+
+Scope: Final Round 1 sanity sweep across JVM micro‑benches and stress tests to confirm that optimizations ON do not regress performance vs OFF in representative scenarios. Each benchmark prints `[DEBUG_LOG] [BENCH]` timings for OFF → ON within a single run. This section records a quick pass confirmation (not 3× medians) and reproduction commands.
+
+Environment:
+- Gradle: 8.7 (stdout enabled, maxParallelForks=1)
+- JVM: as configured by the project toolchain
+- OS/Arch: macOS 14.x (aarch64)
+
+Benches covered (all green; no regressions observed in these runs):
+- Calls/Args: `CallBenchmarkTest`, `CallMixedArityBenchmarkTest` (ARG_BUILDER)
+- PICs: `PicBenchmarkTest` (field/method); `PicInvalidationJvmTest` correctness reconfirmed
+- Expressions/Arithmetic: `ExpressionBenchmarkTest`, `ArithmeticBenchmarkTest` (RVAL_FASTPATH, PRIMITIVE_FASTOPS)
+- Ranges: `RangeBenchmarkTest` (PRIMITIVE_FASTOPS counted loop)
+- List ops: `ListOpsBenchmarkTest` (PRIMITIVE_FASTOPS specializations)
+- Regex: `RegexBenchmarkTest` (REGEX_CACHE with LRU behavior)
+- Locals: `LocalVarBenchmarkTest` (LOCAL_SLOT_PIC + FAST_LOCAL)
+- Concurrency/Pooling: `ConcurrencyCallBenchmarkTest`, `DeepPoolingStressJvmTest`, `MultiThreadPoolingStressJvmTest` (SCOPE_POOL per‑thread)
+
+Reproduce (examples):
+```
+./gradlew :lynglib:jvmTest --tests CallBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests CallMixedArityBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests PicBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests PicInvalidationJvmTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests ExpressionBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests ArithmeticBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests RangeBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests ListOpsBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests RegexBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests LocalVarBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests ConcurrencyCallBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests DeepPoolingStressJvmTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests MultiThreadPoolingStressJvmTest --rerun-tasks
+```
+
+  Summary:
+  - All listed tests passed in this sanity sweep.
+  - For each benchmark’s OFF → ON printouts examined during this pass, ON was equal or faster than OFF; no ON<OFF regressions were observed.
+  - For publication‑grade numbers, use the 3× medians methodology outlined earlier in this document. The existing median tables in previous sections remain representative, and the additional tweaks (Index write, List literal pre‑size, Regex LRU, Field PIC 4‑way + read→write reuse, mixed Int/Real fast‑ops) remained neutral‑to‑positive.
+  
+
+## Quick snapshot — IndexRef PIC + negative miss cache (JVM) — 3× medians (OFF → ON)
+
+Date: 2025-11-11 22:32 (local)
+
+Scope
+- Confirm that the latest changes — IndexRef read/write PIC (stacked on RVAL_FASTPATH) and safe catch‑and‑cache negative entries for Field/Method PICs — do not regress performance. We collected 3× medians for the two expression sub‑benches that are most sensitive to RVAL paths and cross‑checked PICs and ranges.
+
+Environment
+- Gradle: 8.7 (stdout enabled, maxParallelForks=1)
+- JVM: project toolchain default
+- OS/Arch: macOS 14.x (aarch64)
+
+Results (3× medians)
+
+| Area | Benchmark/Test | OFF median (ms) | ON median (ms) | Speedup | Notes |
+|------|-----------------|-----------------:|----------------:|:-------:|-------|
+| RVAL_FASTPATH | ExpressionBenchmarkTest::benchmarkListIndexReads | 304.282 | 229.168 | 1.33× | IndexRef direct fast‑path for ObjList+ObjInt; 4‑way Index PIC handles polymorphic cases |
+| RVAL_FASTPATH | ExpressionBenchmarkTest::benchmarkFieldReadPureReceiver | 275.122 | 194.876 | 1.41× | Monomorphic, immutable receiver path; preserves visibility/optional semantics |
+
+Cross‑checks (from the same session, 1× quick)
+- PicBenchmarkTest::benchmarkFieldGetSetPic — OFF 203.701 ms → ON 117.129 ms (≈1.74×)
+- PicBenchmarkTest::benchmarkMethodPic — OFF 280.806 ms → ON 202.613 ms (≈1.39×)
+- RangeBenchmarkTest::benchmarkIntRangeForIn — OFF 1762.425 ms → ON 806.898 ms (≈2.18×)
+
+Reproduce
+```
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkListIndexReads" --rerun-tasks
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkListIndexReads" --rerun-tasks
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkListIndexReads" --rerun-tasks
+
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkFieldReadPureReceiver" --rerun-tasks
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkFieldReadPureReceiver" --rerun-tasks
+./gradlew :lynglib:jvmTest --tests "ExpressionBenchmarkTest.benchmarkFieldReadPureReceiver" --rerun-tasks
+
+./gradlew :lynglib:jvmTest --tests PicBenchmarkTest --rerun-tasks
+./gradlew :lynglib:jvmTest --tests RangeBenchmarkTest --rerun-tasks
+```
+
+Notes
+- Negative caches are installed only after a real miss throws (cache‑after‑miss), preserving error semantics and invalidation on `layoutVersion` changes.
+- IndexRef PIC augments the existing direct path and uses move‑to‑front promotion; it is keyed on `(classId, layoutVersion)` like other PICs.
+

docs/perf_plan_jvm.md

@@ -0,0 +1,58 @@
+# JVM-only Performance Optimization Plan (Saved)
+
+[//]: # (excludeFromIndex)
+
+Date: 2025-11-10 22:14 (local)
+
+This document captures the agreed next optimization steps so we can restore the plan later if needed.
+
+## Objectives
+- Reduce overhead on the call/argument path.
+- Extend and harden PIC performance (fields/methods/locals).
+- Improve R-value fast paths and interpreter hot nodes (loops, ranges, lists).
+- Make scope frame pooling thread-safe on JVM so it can be enabled by default later.
+- Keep semantics correct and all JVM tests green.
+
+## Prioritized tasks (now)
+1) Call/argument path: fewer allocs, tighter fast paths
+- Extend small-arity zero-alloc path to 6–8 args; benchmark with `CallMixedArityBenchmarkTest`.
+- Splat handling: fast-path single-list splats; benchmark with `CallSplatBenchmarkTest`.
+- Arg builder micro-optimizations: capacity hints, avoid redundant copies, inline simple branches.
+- Optional-chaining fast return (`SKIP_ARGS_ON_NULL_RECEIVER`) coverage audit, add A/B bench.
+
+2) Scope frame pooling: per-thread safety on JVM
+- Replace global deque with ThreadLocal pool on JVM (and Android) actuals.
+- Keep `frameId` uniqueness and pool size cap.
+- Verify with `DeepPoolingStressJvmTest`, `CallPoolingBenchmarkTest`, and spot benches.
+- Do NOT flip default yet; keep `SCOPE_POOL=false` unless explicitly approved.
+
+## Next tasks (queued)
+3) PICs: cheaper misses, broader hits
+- Method PIC 2→3/4 entries (tiny LRU); validate with `PicInvalidationJvmTest`.
+- Field PIC micro-fast path for read-then-write pairs.
+
+4) Locals and slots
+- Ensure `EMIT_FAST_LOCAL_REFS` coverage across compiler sites.
+- Pre-size `slots`/`nameToSlot` when local counts are known; re-run `LocalVarBenchmarkTest`.
+
+5) R-value fast path coverage
+- Cover index reads on primitive lists, pure receivers, assignment RHS where safe.
+- Add benches in `ExpressionBenchmarkTest`.
+
+6) Collections & ranges
+- Tight counted loop for `(Int..Int)` in `for`.
+- Primitive-specialized `ObjList` ops (`map`, `filter`, `sum`, `contains`) under `PRIMITIVE_FASTOPS`.
+
+7) Regex and string ops
+- Cache compiled regex for string literals at compile time; tiny LRU for dynamic patterns under a new `REGEX_CACHE` flag.
+
+8) JIT micro-tweaks
+- Inline tiny helpers; prefer arrays for hot buffers; finalize hot classes where safe.
+
+## Validation matrix
+- Always re-run: `CallBenchmarkTest`, `CallMixedArityBenchmarkTest`, `PicBenchmarkTest`, `ExpressionBenchmarkTest`, `ArithmeticBenchmarkTest`, `CallPoolingBenchmarkTest`, `DeepPoolingStressJvmTest`.
+- Use 3× medians where comparing flags; keep `:lynglib:jvmTest` green.
+
+## Notes
+- All risky changes remain flag-guarded and JVM-only where applicable.
+- Documentation and perf tables updated after each cycle.

docs/proposals/map_literal.md

@@ -0,0 +1,93 @@
+
+# Map literals — refined proposal
+
+Implement JavaScript-like literals for maps. The syntax and semantics align with named arguments in function calls, but map literals are expressions that construct `Map` values.
+
+Keys can be either:
+- string literals: `{ "some key": value }`, or
+- identifiers: `{ name: expr }`, where the key becomes the string `"name"`.
+
+Identifier shorthand inside map literals is supported:
+- `{ name: }` desugars to `{ "name": name }`.
+
+Property access sugar is not provided for maps: use bracket access only, e.g. `m["a"]`, not `m.a`.
+
+Examples:
+
+```lyng
+val x = 2
+val m = { "a": 1, x: x*10, y: }
+assertEquals(1, m["a"])      // string-literal key
+assertEquals(20, m["x"])     // identifier key
+assertEquals(2, m["y"])      // identifier shorthand
+```
+
+Spreads (splats) in map literals are allowed and merged left-to-right with “rightmost wins” semantics:
+
+```lyng
+val base = { a: 1, b: 2 }
+val m = { a: 0, ...base, b: 3, c: 4 }
+assertEquals(1, m["a"])  // base overwrites a:0
+assertEquals(3, m["b"])  // literal overwrites spread
+assertEquals(4, m["c"])  // new key
+```
+
+Trailing commas are allowed (optional):
+
+```lyng
+val m = {
+  "a": 1,
+  b: 2,
+  ...other,
+}
+```
+
+Duplicate keys among literal entries (including identifier shorthand) are a compile-time error:
+
+```lyng
+{ foo: 1, "foo": 2 }   // error: duplicate key "foo"
+{ foo:, foo: 2 }        // error: duplicate key "foo"
+```
+
+Spreads are evaluated at runtime. Overlaps from spreads are resolved by last write wins. If a spread is not a map, or yields a map with non-string keys, it’s a runtime error.
+
+Merging with `+`/`+=` and entries:
+
+```lyng
+("1" => 10) + ("2" => 20)     // Map("1"=>10, "2"=>20)
+{ "1": 10 } + ("2" => 20)     // same
+{ "1": 10 } + { "2": 20 }    // same
+
+var m = { "a": 1 }
+m += ("b" => 2)                 // m = { "a":1, "b":2 }
+```
+
+Rightmost wins on duplicates consistently across spreads and merges. All map merging operations require string keys; encountering a non-string key during merge is a runtime error.
+
+Empty map literal `{}` is not supported to avoid ambiguity with blocks/lambdas. Use `Map()` for an empty map.
+
+Lambda disambiguation
+- A `{ ... }` with typed lambda parameters must have a top-level `->` in its header. The compiler disambiguates by looking for a top-level `->`. If none is found, it attempts to parse a map literal; if that fails, it is parsed as a lambda or block.
+
+Grammar (EBNF)
+
+```
+ws                    = zero or more whitespace (incl. newline/comments)
+map_literal           = '{' ws map_entries ws '}'
+map_entries           = map_entry ( ws ',' ws map_entry )* ( ws ',' )?
+map_entry             = map_key ws ':' ws map_value_opt
+                      | '...' ws expression
+map_key               = string_literal | ID
+map_value_opt         = expression | ε   // ε allowed only if map_key is ID
+```
+
+Notes:
+- Identifier shorthand (`id:`) is allowed only for identifiers, not string-literal keys.
+- Spreads accept any expression; at runtime it must yield a `Map` with string keys.
+- Duplicate keys are detected at compile time among literal keys; spreads are merged at runtime with last-wins.
+
+Rationale
+- The `{ name: value }` style is familiar and ergonomic.
+- Disambiguation with lambdas leverages the required `->` in typed lambda headers.
+- Avoiding `m.a` sidesteps method/field shadowing and keeps semantics clear.
+

docs/proposals/named_args.md

@@ -0,0 +1,67 @@
+# Named arguments proposal
+
+Extend function/method calls to allow setting arguments by name using colon syntax at call sites. This is especially convenient with many parameters and default values.
+
+Examples:
+
+```lyng
+    fun test(a="foo", b="bar", c="bazz") { [a, b, c] }
+
+    assertEquals(test(b: "b"), ["foo", "b", "bazz"])
+    assertEquals(test("a", c: "c"), ["a", "bar", "c"])
+```
+
+Rules:
+
+- Named arguments are optional. If named arguments are present, their order is not important.
+- Named arguments must follow positional arguments; positional arguments cannot follow named ones (the only exception is the syntactic trailing block outside parentheses, see below).
+- A named argument cannot reassign a parameter already set positionally.
+- If the last parameter is already assigned by a named argument (or named splat), the trailing-lambda rule must NOT apply: a following `{ ... }` after the call is an error.
+
+Rationale for using `:` instead of `=` in calls: in Lyng, assignment `=` is an expression; using `:` avoids ambiguity and keeps declarations (`name: Type`) distinct from call sites, where casting uses `as` / `as?`.
+
+Migration note: earlier drafts/examples used `name = value`. The final syntax is `name: value` at call sites.
+
+## Extended call argument splats: named splats
+
+With named arguments, splats (`...`) are extended to support maps as named splats. When a splat evaluates to a Map, its entries provide name→value assignments:
+
+```lyng
+    fun test(a="a", b="b", c="c", d="d") { [a, b, c, d] }
+
+    assertEquals(test("A?", ...Map("d" => "D!", "b" => "B!")), ["A?", "B!", "c", "D!"])
+```
+
+Constraints for named splats:
+
+- Only string keys are allowed in map splats; otherwise, a clean error is thrown.
+- Named splats cannot reassign parameters already set (positionally or by earlier named arguments/splats).
+- Named splats follow the same ordering as named arguments: they must appear after all positional arguments and positional splats.
+
+## Trailing-lambda interaction
+
+Lyng supports a syntactic trailing block after a call: `f(args) { ... }`. With named args/splats, if the last parameter is already assigned by name, the trailing block must not apply and the call is an error:
+
+```lyng
+    fun f(x, onDone) { onDone(x) }
+    f(x: 1) { 42 }    // ERROR: last parameter already assigned by name
+    f(1) { 42 }       // OK
+```
+
+## Errors (non-exhaustive)
+
+- Positional argument after any named argument inside parentheses: error.
+- Positional splat after any named argument: error.
+- Duplicate named assignment (directly or via map splats): error.
+- Unknown parameter name in a named argument/splat: error.
+- Map splat with non-string keys: error.
+- Attempt to target the ellipsis parameter by name: error.
+
+## Notes
+
+- Declarations continue to use `:` for types, while call sites use `:` for named arguments and `as` / `as?` for type casts/checks.
+
+
+
+
+

docs/samples/happy_numbers.lyng.bad

@@ -16,9 +16,16 @@ fun naiveCountHappyNumbers() {
     count
 }
 
+import lyng.time
+
 //
-// After all optimizations it takes ~120ms.
+// After all optimizations it took ~120ms - before.
 //
+for( r in 1..900 ) {
+    val start = Instant.now()
     val found = naiveCountHappyNumbers()
-println("Found happy numbers: "+found)
+    println("Found happy numbers: %d time %s"(found, Instant.now() - start))
     assert( found == 55252 )
+    delay(0.05)
+}
+

docs/samples/helloworld.lyng

@@ -1,2 +1,3 @@
+#!/bin/env jlyng
 
 println("Hello, world!");

docs/samples/sum.lyng

@@ -1,7 +1,7 @@
+#!/bin/env lyng
 /*
     Calculate the limit of Sum( f(n) )
     until it reaches asymptotic limit 0.00001% change
-
     return null or found limit
 */
 fun findSumLimit(f) {

docs/samples/сумма_ряда.lyng.md

@@ -48,6 +48,7 @@ $$ \ln(1+x)=x-{\dfrac {x^{2}}{2}}+{\dfrac {x^{3}}{3}}-\cdots =\sum \limits _{n=0
     }
     assert( почти_равны( 0.0005, 0.000501 ) )
 
-Во многих случаях вычисление $n+1$ члена значительно проще cчитается от предыдущего члена, в нашем случае это можно было бы записать через итератор, что мы вскоре добавим.
+Во многих случаях вычисление $n+1$ члена значительно проще cчитается от предыдущего члена, в нашем случае это можно было бы записать через итератор, см [Iterable] и `flow` в [parallelism].
 
-(продолжение следует)
+[Iterable]: ../Iterable.md
+[parallelism]: ../parallelism.md

docs/serialization.md

@@ -0,0 +1,46 @@
+# Lyng serialization
+
+Lyng has builting binary bit-effective serialization format, called Lynon for LYng Object Notation. It is typed, binary, implements caching, automatic compression, variable-length ints, one-bit Booleans an many nice features. 
+
+It is as simple as:
+
+    import lyng.serialization
+
+    val text = "
+        We hold these truths to be self-evident, that all men are created equal, 
+        that they are endowed by their Creator with certain unalienable Rights, 
+        that among these are Life, Liberty and the pursuit of Happiness.    
+        "
+    val encodedBits = Lynon.encode(text)
+
+    // decode bits source:
+    assertEquals( text, Lynon.decode(encodedBits) )
+    
+    // compression was used automatically
+    assert( text.length > encodedBits.toBuffer().size )
+    >>> void
+
+Any class you create is serializable by default; lynon serializes first constructor fields, then any `var` member fields:
+
+    import lyng.serialization
+
+    class Point(x,y)
+
+    val p = Lynon.decode( Lynon.encode( Point(5,6) ) )
+    
+    assertEquals( 5, p.x )
+    assertEquals( 6, p.y )
+    >>> void
+
+
+just as expected.
+
+Important is to understand that normally `Lynon.decode` wants [BitBuffer], as `Lynon.encode` produces. If you have the regular [Buffer], be sure to convert it:
+
+    buffer.toBitInput()
+
+this possibly creates extra zero bits at the end, as bit content could be shorter than byte-grained but for the Lynon format it does not make sense. Note that when you serialize [BitBuffer], exact number of bits is written. To convert bit buffer to bytes:
+
+    Lynon.encode("hello").toBuffer()
+
+(topic is incomplete and under construction)

docs/time.md

@@ -0,0 +1,215 @@
+# Lyng time functions
+
+Lyng date and time support requires importing `lyng.time` packages. Lyng uses simple yet modern time object models:
+
+- `Instant` class for time stamps with platform-dependent resolution
+- `Duration` to represent amount of time not depending on the calendar, e.g. in absolute units (milliseconds, seconds,
+  hours, days)
+
+## Time instant: `Instant`
+
+Represent some moment of time not depending on the calendar (calendar for example may b e changed, daylight saving time
+can be for example introduced or dropped). It is similar to `TIMESTAMP` in SQL or `Instant` in Kotlin. Some moment of
+time; not the calendar date.
+
+Instant is comparable to other Instant. Subtracting instants produce `Duration`, period in time that is not dependent on
+the calendar, e.g. absolute time period.
+
+It is possible to add or subtract `Duration` to and from `Instant`, that gives another `Instant`.
+
+Instants are converted to and from `Real` number of seconds before or after Unix Epoch, 01.01.1970. Constructor with
+single number parameter constructs from such number of seconds,
+and any instance provide `.epochSeconds` member:
+
+    import lyng.time
+
+    // default constructor returns time now:
+    val t1 = Instant()
+    val t2 = Instant()
+    assert( t2 - t1 < 1.millisecond )
+    assert( t2.epochSeconds - t1.epochSeconds < 0.001 )
+    >>> void
+
+## Constructing
+
+    import lyng.time
+
+    // empty constructor gives current time instant using system clock:
+    val now = Instant()
+
+    // constructor with Instant instance makes a copy:
+    assertEquals( now, Instant(now) )
+
+    // constructing from a number is trated as seconds since unix epoch:
+    val copyOfNow = Instant( now.epochSeconds )
+
+    // note that instant resolution is higher that Real can hold
+    // so reconstructed from real slightly differs:
+    assert( abs( (copyOfNow - now).milliseconds ) < 0.01 )
+    >>> void
+
+The resolution of system clock could be more precise and double precision real number of `Real`, keep it in mind.
+
+## Comparing and calculating periods
+
+    import lyng.time
+    
+    val now = Instant()
+    
+    // you cam add or subtract periods, and compare
+    assert( now - 5.minutes < now )
+    val oneHourAgo = now - 1.hour
+    assertEquals( now, oneHourAgo + 1.hour)
+
+    >>> void
+
+## Getting the max precision
+
+Normally, subtracting instants gives precision to microseconds, which is well inside the jitter
+the language VM adds. Still `Instant()` or `Instant.now()` capture most precise system timer at hand and provide inner
+value of 12 bytes, up to nanoseconds (hopefully). To access it use:
+
+    import lyng.time
+
+    // capture time
+    val now = Instant.now()
+
+    // this is Int value, number of whole epoch 
+    // milliseconds to the moment, it fits 8 bytes Int well
+    val seconds = now.epochWholeSeconds
+    assert(seconds is Int)
+
+    // and this is Int value of nanoseconds _since_ the epochMillis,
+    // it effectively add 4 more mytes int:
+    val nanos = now.nanosecondsOfSecond
+    assert(nanos is Int)
+    assert( nanos in 0..999_999_999 )
+
+    // we can construct epochSeconds from these parts:
+    assertEquals( now.epochSeconds, nanos * 1e-9 + seconds )
+    >>> void
+
+## Truncating to more realistic precision
+
+Full precision Instant is way too long and impractical to store, especially when serializing,
+so it is possible to truncate it to milliseconds, microseconds or seconds:
+
+    import lyng.time
+    import lyng.serialization
+
+    // max supported size (now microseconds for serialized value):
+    // note that encoding return _bit array_ and this is a _bit size_:
+    val s0 = Lynon.encode(Instant.now()).size
+
+    // shorter: milliseconds only
+    val s1 = Lynon.encode(Instant.now().truncateToMillisecond()).size
+
+    // truncated to seconds, good for file mtime, etc:
+    val s2 = Lynon.encode(Instant.now().truncateToSecond()).size 
+    assert( s1 < s0 )
+    assert( s2 < s1 )
+    >>> void
+
+## Formatting instants
+
+You can freely use `Instant` in string formatting. It supports usual sprintf-style formats:
+
+        import lyng.time
+        val now = Instant()
+
+        // will be something like "now: 12:10:05"
+        val currentTimeOnly24 =  "now: %tT"(now)
+
+        // we can extract epoch second with formatting too,
+        // this was since early C time
+
+        // get epoch while seconds from formatting
+        val unixEpoch = "Now is %ts since unix epoch"(now)
+        
+        // and it is the same as now.epochSeconds, int part:
+        assertEquals( unixEpoch, "Now is %d since unix epoch"(now.epochSeconds.toInt()) )
+        >>> void
+
+See
+the [complete list of available formats](https://github.com/sergeych/mp_stools?tab=readme-ov-file#datetime-formatting)
+and the [formatting reference](https://github.com/sergeych/mp_stools?tab=readme-ov-file#printf--sprintf): it all works
+in Lyng as `"format"(args...)`!
+
+## Instant members
+
+| member                         | description                                             |
+|--------------------------------|---------------------------------------------------------|
+| epochSeconds: Real             | positive or negative offset in seconds since Unix epoch |
+| epochWholeSeconds: Int         | same, but in _whole seconds_. Slightly faster           |
+| nanosecondsOfSecond: Int       | offset from epochWholeSeconds in nanos (1)              |
+| isDistantFuture: Bool          | true if it `Instant.distantFuture`                      |
+| isDistantPast: Bool            | true if it `Instant.distantPast`                        |
+| truncateToSecond: Intant       | create new instnce truncated to second                  |  
+| truncateToMillisecond: Instant | truncate new instance with to millisecond               |
+| truncateToMicrosecond: Instant | truncate new instance to microsecond                    |
+
+(1)
+: The value of nanoseconds is to be added to `epochWholeSeconds` to get exact time point. It is in 0..999_999_999 range.
+The precise time instant value therefore needs as for now 12 bytes integer; we might use bigint later (it is planned to
+be added)
+
+## Class members
+
+| member                         | description                                  |
+|--------------------------------|----------------------------------------------|
+| Instant.now()                  | create new instance with current system time |
+| Instant.distantPast: Instant   | most distant instant in past                 |
+| Instant.distantFuture: Instant | most distant instant in future               |
+
+# `Duraion` class
+
+Represent absolute time distance between two `Instant`.
+
+    import lyng.time
+    val t1 = Instant()
+
+    // yes we can delay to period, and it is not blocking. is suspends!
+    delay(1.millisecond)
+
+    val t2 = Instant()
+    // be suspend, so actual time may vary:
+    assert( t2 - t1 >= 1.millisecond)
+    assert( t2 - t1 < 100.millisecond)
+    >>> void
+
+Duration can be converted from numbers, like `5.minutes` and so on. Extensions are created for
+`Int` and `Real`, so for n as Real or Int it is possible to create durations::
+
+- `n.millisecond`, `n.milliseconds`
+- `n.second`, `n.seconds`
+- `n.minute`, `n.minutes`
+- `n.hour`, `n.hours`
+- `n.day`, `n.days`
+
+The bigger time units like months or years are calendar-dependent and can't be used with `Duration`.
+
+Each duration instance can be converted to number of any of these time units, as `Real` number, if `d` is a `Duration`
+instance:
+
+- `d.microseconds`
+- `d.milliseconds`
+- `d.seconds`
+- `d.minutes`
+- `d.hours`
+- `d.days`
+
+for example
+
+    import lyng.time
+    assertEquals( 60, 1.minute.seconds )
+    assertEquals( 10.milliseconds, 0.01.seconds )
+
+    >>> void
+
+# Utility functions
+
+## delay(duration: Duration)
+
+Suspends current coroutine for at least the specified duration.
+
+

docs/tutorial.md

@@ -1,8 +1,3 @@
----
-gitea: none
-include_toc: true
----
-
 # Lyng tutorial
 
 Lyng is a very simple language, where we take only most important and popular features from
@@ -13,9 +8,13 @@ __Other documents to read__ maybe after this one:
 
 - [Advanced topics](advanced_topics.md), [declaring arguments](declaring_arguments.md)
 - [OOP notes](OOP.md), [exception handling](exceptions_handling.md)
-- [math in Lyng](math.md)
+- [math in Lyng](math.md), [the `when` statement](when.md)
-- Some class references: [List], [Real], [Range], [Iterable], [Iterator]
+- [time](time.md) and [parallelism](parallelism.md)
-- Some samples: [combinatorics](samples/combinatorics.lyng.md), national vars and loops: [сумма ряда](samples/сумма_ряда.lyng.md). More at [samples folder](samples)
+- [parallelism] - multithreaded code, coroutines, etc.
+- Some class
+  references: [List], [Set], [Map], [Real], [Range], [Iterable], [Iterator], [time manipulation](time.md), [Array], [RingBuffer], [Buffer].
+- Some samples: [combinatorics](samples/combinatorics.lyng.md), national vars and
+  loops: [сумма ряда](samples/сумма_ряда.lyng.md). More at [samples folder](samples)
 
 # Expressions
 
@@ -118,6 +117,123 @@ These operators return rvalue, unmodifiable.
 
 ## Assignment return r-value!
 
+Naturally, assignment returns its value:
+
+    var x
+    x = 11
+    >>> 11
+
+rvalue means you cant assign the result if the assignment
+
+    var x
+    assertThrows { (x = 11) = 5 }
+    void
+    >>> void
+
+This also prevents chain assignments so use parentheses:
+
+    var x
+    var y
+    x = (y = 1)
+    >>> 1
+
+## Nullability
+
+When the value is `null`, it might throws `NullReferenceException`, the name is somewhat a tradition. To avoid it
+one can check it against null or use _null coalescing_. The null coalescing means, if the operand (left) is null,
+the operation won't be performed and the result will be null. Here is the difference:
+
+    val ref = null
+    assertThrows {  ref.field }
+    assertThrows {  ref.method() }
+    assertThrows {  ref.array[1] }
+    assertThrows {  ref[1] }
+    assertThrows {  ref() }
+    
+    assert( ref?.field == null )
+    assert( ref?.method() == null )
+    assert( ref?.array?[1] == null )
+    assert( ref?[1] == null )
+    assert( ref?() == null )
+    >>> void
+
+There is also "elvis operator", null-coalesce infix operator '?:' that returns rvalue if lvalue is `null`:
+
+    null ?: "nothing"
+    >>> "nothing"
+
+## Utility functions
+
+The following functions simplify nullable values processing and
+allow to improve code look and readability. There are borrowed from Kotlin:
+
+### let
+
+`value.let {}` passes to the block value as the single parameter (by default it is assigned to `it`) and return block's
+returned value. It is useful dealing with null or to
+get a snapshot of some externally varying value, or with `?.` to process nullable value in a safe manner:
+
+    // this state is changed from parallel processes
+    class GlobalState(nullableParam)
+    
+    val state = GlobalState(null)
+
+    fun sample() {
+        state.nullableParam?.let { "it's not null: "+it} ?: "it's null"
+    }
+    assertEquals(sample(), "it's null")
+    state.nullableParam = 5
+    assertEquals(sample(), "it's not null: 5")
+    >>> void
+
+This is the same as:
+
+    fun sample() {
+        val it = state.nullableParam
+        if( it != null )  "it's not null: "+it else "it's null"
+    }
+
+The important is that nullableParam got a local copy that can't be changed from any
+parallel thread/coroutine. Remember: Lyng _is __not__ a single-threaded language_.
+
+## Also
+
+Much like let, but it does not alter returned value:
+
+    assert( "test".also { println( it + "!") } == "test" )
+    >>> test!
+    >>> void
+
+While it is not altering return value, the source object could be changed:
+
+    class Point(x,y)
+    val p = Point(1,2).also { it.x++ }
+    assertEquals(p.x, 2)
+    >>> void
+
+## apply
+
+It works much like `also`, but is executed in the context of the source object:
+
+    class Point(x,y)
+    // see the difference: apply changes this to newly created Point:
+    val p = Point(1,2).apply { x++; y++ }
+    assertEquals(p, Point(2,3))
+    >>> void
+
+## run
+
+Executes a block after it returning the value passed by the block. for example, can be used with elvis operator:
+
+    var someVar = null
+    val result = someVar ?: run {
+      someVar = 121
+      "reset"
+    }
+    assertEquals("reset", result)
+    assertEquals(121, someVar)
+    >>> void
+
 ## Math
 
 It is rather simple, like everywhere else:
@@ -154,6 +270,8 @@ Logical operation could be used the same
 |   ===    |     | Any               | (2)      |
 |   !==    |     | Any               | (2)      |
 |    !=    |     | Any               | (1)      |
+|    =~    |     |                   | (3)      |
+|    !~    |     |                   | (3)      |
 | ++a, a++ |     | Int               |          |
 | --a, a-- |     | Int               |          |
 
@@ -165,6 +283,9 @@ Logical operation could be used the same
 singleton object, like `null`, are referentially equal too, while string different literals even being equal are most
 likely referentially not equal
 
+(3)
+: Implemented now in String and Regex as regular expression match and not match, see [Regex].
+
 Reference quality and object equality example:
 
     assert( null == null)  // singletons
@@ -361,7 +482,6 @@ after function call, it is treated as a last argument to the call, e.g.:
     assert( [11, 21, 31] == mapped)
     >>> void
 
-
 # Lists (aka arrays)
 
 Lyng has built-in mutable array class `List` with simple literals:
@@ -369,7 +489,8 @@ Lyng has built-in mutable array class `List` with simple literals:
     [1, "two", 3.33].size
     >>> 3
 
-[List] is an implementation of the type `Array`, and through it `Collection` and [Iterable].
+[List] is an implementation of the type `Array`, and through it `Collection` and [Iterable]. Please read [Iterable],
+many collection based methods are implemented there.
 
 Lists can contain any type of objects, lists too:
 
@@ -393,7 +514,7 @@ Of course, you can splat from anything that is List (or list-like, but it will b
     val a = ["one", "two"]
     val b = [10.1, 20.2]
     ["start", ...b, ...a, "end"]
-    >>> ["start", 10.1, 20.2, "one", "two", "end"]
+    >>> [start,10.1,20.2,one,two,end]
 
 Of course, you can set any list element:
 
@@ -427,10 +548,12 @@ The simplest way to concatenate lists is using `+` and `+=`:
     list += [2, 1]      
     // or you can append a single element:
     list += "end"
-    assert( list == [1, 2, 2, 1, "end"])
+    assertEquals( list, [1, 2, 2, 1, "end"])
+    void
     >>> void
 
-***Important note***: the pitfall of using `+=` is that you can't append in [Iterable] instance as an object: it will always add all its contents. Use `list.add` to add a single iterable instance:
+***Important note***: the pitfall of using `+=` is that you can't append in [Iterable] instance as an object: it will
+always add all its contents. Use `list.add` to add a single iterable instance:
 
     var list = [1, 2]
     val other = [3, 4]
@@ -458,7 +581,6 @@ Use `list.add` to avoid confusion:
     assert( list == [1, 2, [3, 4], (10..12)])
     >>> void
 
-
 To add elements to the list:
 
     val x = [1,2]
@@ -469,64 +591,149 @@ To add elements to the list:
     assert( x == [1, 2, 3, "the", "end"])
     >>> void
 
-Self-modifying concatenation by `+=` also works:
+Self-modifying concatenation by `+=` also works (also with single elements):
 
     val x = [1, 2]
     x += [3, 4]
-    assert( x == [1, 2, 3, 4])
+    x += 5
+    assert( x == [1, 2, 3, 4, 5])
     >>> void
 
-You can insert elements at any position using `addAt`:
+You can insert elements at any position using `insertAt`:
 
     val x = [1,2,3]
-    x.addAt(1, "foo", "bar")
+    x.insertAt(1, "foo", "bar")
     assert( x == [1, "foo", "bar", 2, 3])
     >>> void
 
 Using splat arguments can simplify inserting list in list:
 
     val x = [1, 2, 3]
-    x.addAt( 1, ...[0,100,0])
+    x.insertAt( 1, ...[0,100,0])
     x
     >>> [1,0,100,0,2,3]
 
-Using negative indexes can insert elements as offset from the end, for example:
-
-    val x = [1,2,3]
-    x.addAt(-1, 10)
-    x
-    >>> [1, 2, 10, 3]
-
 Note that to add to the end you still need to use `add` or positive index of the after-last element:
 
     val x = [1,2,3]
-    x.addAt(3, 10)
+    x.insertAt(3, 10)
     x
     >>> [1,2,3,10]
 
+but it is much simpler, and we recommend to use '+='
+
+    val x = [1,2,3]
+    x += 10
+    >>> [1,2,3,10]
+
 ## Removing list items
 
     val x = [1, 2, 3, 4, 5]
     x.removeAt(2)
     assert( x == [1, 2, 4, 5])
     // or remove range (start inclusive, end exclusive):
-    x.removeRangeInclusive(1,2)    
+    x.removeRange(1..2)    
     assert( x == [1, 5])
     >>> void
 
-Again, you can use negative indexes. For example, removing last elements like:
+There is a shortcut to remove the last elements:
 
     val x = [1, 2, 3, 4, 5]
 
     // remove last:
-    x.removeAt(-1)
+    x.removeLast()
     assert( x == [1, 2, 3, 4])
     
     // remove 2 last:
-    x.removeRangeInclusive(-2,-1)
+    x.removeLast(2)
-    assert( x == [1, 2])
+    assertEquals( [1, 2], x)
     >>> void
 
+You can get ranges to extract a portion from a list:
+
+    val list = [1, 2, 3, 4, 5]
+    assertEquals( [1,2,3], list[..2])
+    assertEquals( [1,2,], list[..<2])
+    assertEquals( [4,5], list[3..])
+    assertEquals( [2,3], list[1..2])
+    assertEquals( [2,3], list[1..<3])
+    >>> void
+
+# Buffers
+
+[Buffer] is a special implementation of an [Array] of unsigned bytes, in the
+[separate file](Buffer.md).
+
+# Sets
+
+Set are unordered collection of unique elements, see [Set]. Sets are [Iterable] but have no indexing access.
+
+    assertEquals( Set(3, 2, 1), Set( 1, 2, 3))
+    assert( 5 !in Set(1, 2, 6) )
+    >>> void
+
+Please see [Set] for detailed description.
+
+# Maps
+
+Maps are unordered collections of key-value pairs, where keys are unique. Maps are also [Iterable].
+
+You can create them either with the classic constructor (still supported):
+
+    val old = Map( "foo" => 77, "bar" => "buzz" )
+    assertEquals( old["foo"], 77 )
+    >>> void
+
+…or with map literals, which are often more convenient:
+
+    val x = 10
+    val y = 10
+    val m = { "a": 1, x: x * 2, y: }
+    // identifier keys become strings; `y:` is shorthand for y: y
+    assertEquals(1, m["a"])      // string-literal key
+    assertEquals(20, m["x"])     // identifier key
+    assertEquals(10, m["y"])     // shorthand
+    >>> void
+
+Map literals support trailing commas for nicer diffs:
+
+    val m2 = {
+        "a": 1,
+        b: 2,
+    }
+    assertEquals(1, m2["a"]) 
+    assertEquals(2, m2["b"]) 
+    >>> void
+
+You can spread other maps inside a literal with `...`. Items merge left-to-right and the rightmost value wins:
+
+    val base = { a: 1, b: 2 }
+    val merged = { a: 0, ...base, b: 3, c: 4 }
+    assertEquals(1, merged["a"])  // base overwrites a:0
+    assertEquals(3, merged["b"])  // literal overwrites spread
+    assertEquals(4, merged["c"])  // new key
+    >>> void
+
+Merging also works with `+` and `+=`, and you can combine maps and entries conveniently:
+
+    val m3 = { "a": 10 } + ("b" => 20)
+    assertEquals(10, m3["a"]) 
+    assertEquals(20, m3["b"]) 
+
+    var m4 = ("x" => 1) + ("y" => 2)      // entry + entry → Map
+    m4 += { z: 3 }                          // merge literal
+    assertEquals(1, m4["x"]) 
+    assertEquals(2, m4["y"]) 
+    assertEquals(3, m4["z"]) 
+    >>> void
+
+Notes:
+- Access keys with brackets: `m["key"]`. There is no `m.key` sugar.
+- Empty `{}` remains a block/lambda; use `Map()` to create an empty map.
+- When you need computed (expression) keys or non-string keys, use `Map(...)` constructor with entries, e.g. `Map( ("a" + "b") => 1 )`, then merge with a literal if needed: `{ base: } + (computedKey => 42)`.
+
+Please see the [Map] reference for a deeper guide.
+
 # Flow control operators
 
 ## if-then-else
@@ -552,6 +759,101 @@ Or, more neat:
     >>> just 3
     >>> void
 
+## When
+
+See also: [Comprehensive guide to `when`](when.md)
+
+It is very much like the kotlin's:
+
+    fun type(x) {
+        when(x) {
+            in 'a'..'z', in 'A'..'Z' -> "letter"
+            in '0'..'9' -> "digit"
+            '$' -> "dollar"
+            "EUR" -> "crap"
+            in ['@', '#', '^'] -> "punctuation1"
+            in "*&.," -> "punctuation2"
+            else -> "unknown"
+        }
+    }
+    assertEquals("digit", type('3'))
+    assertEquals("dollar", type('$'))
+    assertEquals("crap", type("EUR"))
+    >>> void
+
+Notice, several conditions can be grouped with a comma.
+Also, you can check the type too:
+
+    fun type(x) {
+        when(x) {
+            "42", 42 -> "answer to the great question"
+            is Real, is Int -> "number"
+            is String -> {
+                for( d in x ) {
+                    if( d !in '0'..'9' ) 
+                        break "unknown"
+                }
+                else "number"
+            }
+        }
+    }
+    assertEquals("number", type(5))
+    assertEquals("number", type("153"))
+    assertEquals("number", type(π/2))
+    assertEquals("unknown", type("12%"))
+    assertEquals("answer to the great question", type(42))
+    assertEquals("answer to the great question", type("42"))
+    >>> void
+
+### supported when conditions:
+
+#### Contains:
+
+You can thest that _when expression_ is _contained_, or not contained, in some object using `in container` and
+`!in container`. The container is any object that provides `contains` method, otherwise the runtime exception will be
+thrown.
+
+Typical builtin types that are containers (e.g. support `contains`):
+
+| class        | notes                                          |
+|--------------|------------------------------------------------|
+| [Collection] | contains an element (1)                        |
+| Array        | faster maybe that Collection's                 |
+| List         | faster than Array's                            |
+| String       | character in string or substring in string (3) |
+| Range        | object is included in the range (2)            |
+| Buffer       | byte is in buffer                              |
+| RingBuffer   | object is in buffer                            |
+
+(1)
+: Iterable is not the container as it can be infinite
+
+(2)
+: Depending on the inclusivity and open/closed range parameters. BE careful here: String range is allowed, but it is
+usually not what you expect of it:
+
+    assert( "more" in "a".."z") // string range ok
+    assert( 'x' !in "a".."z") // char in string range: probably error
+    assert( 'x' in 'a'..'z') // character range: ok
+    assert( "x" !in 'a'..'z') // string in character range: could be error
+    >>> void
+
+(3)
+: `String` also can provide array of characters directly with `str.characters()`, which is [Iterable] and [Array].
+String itself is not iterable as otherwise it will interfere when adding strigns to lists (it will add _characters_ it
+it would be iterable).
+
+So we recommend not to mix characters and string ranges; use `ch in str` that works
+as expected:
+
+    "foo" in "foobar"
+    >>> true
+
+and also character inclusion:
+
+    'o' in "foobar"
+    >>> true
+
 ## while
 
 Regular pre-condition while loop, as expression, loop returns the last expression as everything else:
@@ -617,7 +919,8 @@ We can skip the rest of the loop and restart it, as usual, with `continue` opera
     "found even numbers: " + countEven
     >>> "found even numbers: 5"
 
-`continue` can't "return" anything: it just restarts the loop. It can use labeled loops to restart outer ones (we intentionally avoid using for loops here):
+`continue` can't "return" anything: it just restarts the loop. It can use labeled loops to restart outer ones (we
+intentionally avoid using for loops here):
 
     var count = 0
     var total = 0
@@ -677,7 +980,8 @@ flowchart TD
 
 So the returned value, as seen from diagram could be one of:
 
-- `void`, if the loop was not executed, e.g. `condition` was initially false, and there was no `else` clause, or if the empty break was executed.
+- `void`, if the loop was not executed, e.g. `condition` was initially false, and there was no `else` clause, or if the
+  empty break was executed.
 - value returned from `break value' statement
 - value returned from the `else` clause, of the loop was not broken
 - value returned from the last execution of loop body, if there was no `break` and no `else` clause.
@@ -701,7 +1005,8 @@ available in the condition:
     } while( continueLoop )
     >>> "OK"
 
-This is sometimes convenient when condition is complex and has to be calculated inside the loop body. Notice the value returning by the loop:
+This is sometimes convenient when condition is complex and has to be calculated inside the loop body. Notice the value
+returning by the loop:
 
     fun readLine() { "done: result" }
     val result = do {
@@ -712,7 +1017,6 @@ This is sometimes convenient when condition is complex and has to be calculated
 
 Suppose readLine() here reads some stream of lines.
 
-
 ## For loops
 
 For loop are intended to traverse collections, and all other objects that supports
@@ -755,7 +1059,8 @@ We can use labels too:
 
 # Exception handling
 
-Very much like in Kotlin. Try block returns its body block result, if no exception was cauht, or the result from the catch block that caught the exception:
+Very much like in Kotlin. Try block returns its body block result, if no exception was cauht, or the result from the
+catch block that caught the exception:
 
     var error = "not caught"
     var finallyCaught = false
@@ -808,7 +1113,6 @@ many more.
 
 - see [exception handling](exceptions_handling.md) for detailed exceptions tutorial and reference.
 
-
 # Self-assignments in expression
 
 There are auto-increments and auto-decrements:
@@ -873,6 +1177,38 @@ and you can use ranges in for-loops:
 
 See [Ranges](Range.md) for detailed documentation on it.
 
+# Time routines
+
+These should be imported from [lyng.time](time.md). For example:
+
+    import lyng.time
+
+    val now = Instant()
+    val hourAgo = now - 1.hour
+
+See [more docs on time manipulation](time.md)
+
+# Enums
+
+For the moment, only simple enums are implemented. Enum is a list of constants, represented also by their
+_ordinal_ - [Int] value.
+
+    enum Color {
+        RED, GREEN, BLUE
+    }
+    
+    assert( Color.RED is Color )
+
+    assertEquals( 2, Color.BLUE.ordinal )
+    assertEquals( "BLUE", Color.BLUE.name )
+    
+    assertEquals( [Color.RED,Color.GREEN,Color.BLUE], Color.entries)
+    assertEquals( Color.valueOf("GREEN"), Color.GREEN )
+    >>> void
+
+Enums are serialized as ordinals. Please note that due to caching, serialized string arrays could be even more compact
+than enum arrays, until `Lynon.encodeTyped` will be implemented.
+
 # Comments
 
     // single line comment
@@ -899,13 +1235,38 @@ See also [math operations](math.md)
 
 The type for the character objects is `Char`.
 
+### String literal escapes
+
+| escape | ASCII value           |
+|--------|-----------------------|
+| \n     | 0x10, newline         |
+| \r     | 0x13, carriage return |
+| \t     | 0x07, tabulation      |
+| \\     | \ slash character     |
+| \"     | " double quote        |
+
+Other `\c` combinations, where c is any char except mentioned above, are left intact, e.g.:
+
+    val s = "\a"
+    assert(s[0] == '\')
+    assert(s[1] == 'a')
+    >>> void
+
+same as:
+
+    val s = "\\a"
+    assert(s[0] == '\')
+    assert(s[1] == 'a')
+    >>> void
+
 ### Char literal escapes
 
 Are the same as in string literals with little difference:
 
 | escape | ASCII value           |
-|--------|-------------------|
+|--------|-----------------------|
 | \n     | 0x10, newline         |
+| \r     | 0x13, carriage return |
 | \t     | 0x07, tabulation      |
 | \\     | \ slash character     |
 | \'     | ' apostrophe          |
@@ -920,38 +1281,113 @@ Are the same as in string literals with little difference:
 | code   | Int  | Unicode code for the character |
 |        |      |                                |
 
-
 ## String details
 
-Strings are much like Kotlin ones:
+Strings are arrays of Unicode characters. It can be indexed, and indexing will
+return a valid Unicode character at position. No utf hassle:
 
-    "Hello".length
+    "Парашют"[5]
+    >>> 'ю'
+
+Its length is, of course, in characters:
+
+    "разум".length
     >>> 5
+
 And supports growing set of kotlin-borrowed operations, see below, for example:
 
     assertEquals("Hell", "Hello".dropLast(1))
     >>> void
 
+To format a string use sprintf-style modifiers like:
+
+    val a = "hello"
+    val b = 11
+    assertEquals( "hello:11", "%s:%d"(a, b) )
+    assertEquals( " hello:    11", "%6s:%6d"(a, b) )
+    assertEquals( "hello :11    ", "%-6s:%-6d"(a, b) )
+    >>> void
+
+List of format specifiers closely resembles C sprintf() one.
+See [format specifiers](https://github.com/sergeych/mp_stools?tab=readme-ov-file#sprintf-syntax-summary), this is doe
+using [mp_stools kotlin multiplatform library](https://github.com/sergeych/mp_stools). Currently supported Lyng types
+are `String`, `Int`, `Real`, `Bool`, the rest are displayed using their `toString()` representation.
+
+This list will be extended.
+
+To get the substring use:
+
+    assertEquals("pult", "catapult".takeLast(4))
+    assertEquals("cat", "catapult".take(3))
+    assertEquals("cat", "catapult".dropLast(5))
+    assertEquals("pult", "catapult".drop(4))
+    >>> void
+
+And to get a portion you can slice it with range as the index:
+
+    assertEquals( "tap", "catapult"[ 2 .. 4 ])
+    assertEquals( "tap", "catapult"[ 2 ..< 5 ])
+    >>> void
+
+Open-ended ranges could be used to get start and end too:
+
+    assertEquals( "cat", "catapult"[ ..< 3 ])
+    assertEquals( "cat", "catapult"[ .. 2 ])
+    assertEquals( "pult", "catapult"[ 4.. ])
+    >>> void
+
 ### String operations
 
-Concatenation is a `+`: `"hello " + name` works as expected. No confusion.
+Concatenation is a `+`: `"hello " + name` works as expected. No confusion. There is also
+[Regex] support for strings, see the link, for example, whole string match:
+
+    assert( !"123".matches( "\d\d".re ) )
+    assert( "123".matches( "\d\d\d".re ) )
+    >>> void
+
+Extraction:
+
+    "abcd42def"[ "\d+".re ].value
+    >>> "42"
+
+Part match:
+
+    assert( "abc foo def" =~ "f[oO]+".re )
+    assert( "foo" == $~.value )
+    >>> void
 
 Typical set of String functions includes:
 
 | fun/prop           | description / notes                                        |
-|------------------|------------------------------------------------------------|
+|--------------------|------------------------------------------------------------|
 | lower()            | change case to unicode upper                               |
 | upper()            | change case to unicode lower                               |
+| trim()             | trim space chars from both ends                            |
 | startsWith(prefix) | true if starts with a prefix                               |
+| endsWith(prefix)   | true if ends with a prefix                                 |
 | take(n)            | get a new string from up to n first characters             |
 | takeLast(n)        | get a new string from up to n last characters              |
 | drop(n)            | get a new string dropping n first chars, or empty string   |
 | dropLast(n)        | get a new string dropping n last chars, or empty string    |
 | size               | size in characters like `length` because String is [Array] |
+| (args...)          | sprintf-like formatting, see [string formatting]           |
+| [index]            | character at index                                         | 
+| [Range]            | substring at range (2)                                     |
+| [Regex]            | find first match of regex, like [Regex.find] (2)           |
+| s1 + s2            | concatenation                                              |
+| s1 += s2           | self-modifying concatenation                               |
+| toReal()           | attempts to parse string as a Real value                   |
+| toInt()            | parse string to Int value                                  |
+| characters()       | create [List] of characters (1)                            |
+| encodeUtf8()       | returns [Buffer] with characters encoded to utf8           |
+| matches(re)        | matches the regular expression (2)                         |
+|                    |                                                            |
 
+(1)
+: List is mutable therefore a new copy is created on each call.
 
-
+(2)
-
+: See [Regex]
 
 ### Literals
 
@@ -960,16 +1396,45 @@ String literal could be multiline:
     "Hello
     World"
 
-though multiline literals is yet work in progress.
+In this case, it will be passed literally ot "hello\n World". But, if there are
+several lines with common left indent, it will be removed, also, forst and last lines,
+if blank, will be removed too, for example:
+
+    println("
+            This is a multiline text.
+            This is a second line.
+        ")
+    >>> This is a multiline text.
+    >>> This is a second line.
+    >>> void
+
+- as expected, empty lines and common indent were removed. It is much like kotlin's `""" ... """.trimIndent()`
+  technique, but simpler ;)
 
 # Built-in functions
 
 See [math functions](math.md). Other general purpose functions are:
 
 | name                                  | description                                                |
-|----------------------------------------------|----------------------------------------------------------|
+|---------------------------------------|------------------------------------------------------------|
-| assert(condition,message="assertion failed") | runtime code check. There will be an option to skip them |
+| assert(condition, fn)                 | (1) runtime code check with generic or custom nessage `fn` |
-| println(args...)                             | Open for overriding, it prints to stdout.                |
+| assertEquals(a,b)                     |                                                            |
+| assertNotEquals(a,b)                  |                                                            |
+| assertTrows { /* block */ }           |                                                            |
+| check(condition, message=<default>)   | throws IllegalStateException" of condition isn't met       |
+| require(condition, message=<default>) | throws IllegalArgumentException" of condition isn't met    |
+| println(args...)                      | Open for overriding, it prints to stdout with newline.     |
+| print(args...)                        | Open for overriding, it prints to stdout without newline.  |
+| flow {}                               | create flow sequence, see [parallelism]                    |
+| delay, launch, yield                  | see [parallelism]                                          |
+| cached(builder)                       | remembers builder() on first invocation and return it then |
+| let, also, apply, run                 | see above, flow controls                                   |
+
+(1)
+: `fn` is optional lambda returning string message to add to exception string. 
+Lambda avoid unnecessary execution if assertion is not failed. for example:
+
+    assert( x < 10 ) { "x=%s should be < 10"(x) } 
 
 # Built-in constants
 
@@ -979,9 +1444,96 @@ See [math functions](math.md). Other general purpose functions are:
 | π                                   | See [math](math.md)          |
 
 [List]: List.md
+
 [Iterable]: Iterable.md
+
 [Iterator]: Iterator.md
+
 [Real]: Real.md
+
 [Range]: Range.md
 
+[String]: development/String.md
 
+[string formatting]: https://github.com/sergeych/mp_stools?tab=readme-ov-file#sprintf-syntax-summary
+
+[Set]: Set.md
+
+[Map]: Map.md
+
+[Buffer]: Buffer.md
+
+[parallelism]: parallelism.md
+
+[RingBuffer]: RingBuffer.md
+
+[Collection]: Collection.md
+
+[Array]: Array.md
+
+[Regex]: Regex.md
+
+## Multiple Inheritance (quick start)
+
+Lyng supports multiple inheritance (MI) with simple, predictable rules. For a full reference see OOP notes, this is a quick, copy‑paste friendly overview.
+
+Declare a class with multiple bases and pass constructor arguments to each base in the header:
+
+```
+class Foo(val a) {
+    var tag = "F"
+    fun runA() { "ResultA:" + a }
+    fun common() { "CommonA" }
+    private fun privateInFoo() {}
+    protected fun protectedInFoo() {}
+}
+
+class Bar(val b) {
+    var tag = "B"
+    fun runB() { "ResultB:" + b }
+    fun common() { "CommonB" }
+}
+
+class FooBar(a, b) : Foo(a), Bar(b) {
+    // Inside class bodies you can qualify with this@Type
+    fun fromFoo() { this@Foo.common() }
+    fun fromBar() { this@Bar.common() }
+}
+
+val fb = FooBar(1, 2)
+assertEquals("ResultA:1", fb.runA())
+assertEquals("ResultB:2", fb.runB())
+
+// Unqualified ambiguous member uses the first base (leftmost)
+assertEquals("CommonA", fb.common())
+
+// Disambiguate with casts
+assertEquals("CommonB", (fb as Bar).common())
+assertEquals("CommonA", (fb as Foo).common())
+
+// Field collisions: unqualified read/write uses the first in order
+assertEquals("F", fb.tag)
+fb.tag = "X"
+assertEquals("X", fb.tag)          // Foo.tag updated
+assertEquals("X", (fb as Foo).tag) // qualified read: Foo.tag
+assertEquals("B", (fb as Bar).tag) // qualified read: Bar.tag
+
+// Qualified write targets the chosen base storage
+(fb as Bar).tag = "Y"
+assertEquals("X", (fb as Foo).tag)
+assertEquals("Y", (fb as Bar).tag)
+
+// Optional casts with safe call
+class Buzz : Bar(3)
+val buzz = Buzz()
+assertEquals("ResultB:3", buzz.runB())
+assertEquals("ResultB:3", (buzz as? Bar)?.runB())
+assertEquals(null, (buzz as? Foo)?.runA())
+```
+
+Notes:
+- Resolution order uses C3 MRO (active): deterministic, monotonic order suitable for diamonds and complex hierarchies. Example: for `class D() : B(), C()` where both `B()` and `C()` derive from `A()`, the C3 order is `D → B → C → A`. The first visible match wins.
+- `private` is visible only inside the declaring class; `protected` is visible from the declaring class and any of its transitive subclasses. Qualification (`this@Type`) or casts do not bypass visibility.
+- Safe‑call `?.` works with `as?` for optional dispatch.
+
+To get details on OOP in Lyng, see [OOP notes](oop.md).

docs/when.md

@@ -0,0 +1,239 @@
+# The `when` statement (expression)
+
+Lyng provides a concise multi-branch selection with `when`, heavily inspired by Kotlin. In Lyng, `when` is an expression: it evaluates to a value. If the selected branch contains no value (e.g., it ends with `void` or calls a void function like `println`), the whole `when` expression evaluates to `void`.
+
+Currently, Lyng implements the "subject" form: `when(value) { ... }`. The subject-less form `when { condition -> ... }` is not implemented yet.
+
+## Quick examples
+
+    val r1 = when("a") {
+        "a" -> "ok"
+        else -> "nope"
+    }
+    assertEquals("ok", r1)
+    
+    val r2 = when(5) {
+        3 -> "no"
+        4 -> "no"
+        else -> "five"
+    }
+    assertEquals("five", r2)
+    
+    val r3 = when(5) {
+        3 -> "no"
+        4 -> "no"
+    }
+    // no matching case and no else → `void`
+    assert(r3 == void)
+    >>> void
+
+## Syntax
+
+    when(subject) {
+        condition1 [, condition2, ...] -> resultExpressionOrBlock
+        conditionN -> result
+        else -> fallback
+    }
+
+- Commas group multiple conditions for one branch.
+- First matching branch wins; there is no fall‑through.
+- `else` is optional. If omitted and nothing matches, the result is `void`.
+
+## Matching rules (conditions)
+
+Within `when(subject)`, each condition is evaluated against the already evaluated `subject`. Lyng supports:
+
+1) Equality match (default)
+- Any expression value can be used as a condition. It matches if it is equal to `subject`.
+- Equality relies on Lyng’s comparison (`compareTo(...) == 0`). For user types, implement comparison accordingly.
+
+    when(x) {
+        0 -> "zero"
+        "EUR" -> "currency"
+    }
+    >>> void
+
+2) Type checks: `is` and `!is`
+- Check whether the subject is an instance of a class.
+- Works with built‑in classes and user classes.
+
+    fun typeOf(x) {
+        when(x) {
+            is Real, is Int -> "number"
+            is String -> "string"
+            else -> "other"
+        }
+    }
+    assertEquals("number", typeOf(5))
+    assertEquals("string", typeOf("hi"))
+    >>> void
+
+3) Containment checks: `in` and `!in`
+- `in container` matches if `container.contains(subject)` is true.
+- `!in container` matches if `contains(subject)` is false.
+- Any object that provides `contains(item)` can act as a container.
+
+Common containers:
+- Ranges (e.g., `'a'..'z'`, `1..10`, `1..<10`, `..5`, `5..`)
+- Lists, Sets, Arrays, Buffers
+- Strings (character or substring containment)
+
+Examples:
+
+    when('e') {
+        in 'a'..'c' -> "small"
+        in 'a'..'z' -> "letter"
+        else -> "other"
+    }
+    >>> "letter"
+    
+    when(5) {
+        in [1,2,3,4,6] -> "no"
+        in [7,0,9] -> "no"
+        else -> "ok"
+    }
+    >>> "ok"
+    
+    when(5) {
+        in [1,2,3,4,6] -> "no"
+        in [7,0,9] -> "no"
+        in [-1,5,11] -> "yes"
+        else -> "no"
+    }
+    >>> "yes"
+    
+    when(5) {
+        !in [1,2,3,4,6,5] -> "no"
+        !in [7,0,9,5] -> "no"
+        !in [-1,15,11] -> "ok"
+        else -> "no"
+    }
+    >>> "ok"
+    
+    // String containment
+    "foo" in "foobar"   // true (substring)
+    'o' in "foobar"      // true (character)
+    >>> true
+
+Notes on mixed String/Char ranges:
+- Prefer character ranges for characters: `'a'..'z'`.
+- `"a".."z"` is a String range and may not behave as you expect with `Char` subjects.
+
+    assert( "more" in "a".."z")
+    assert( 'x' !in "a".."z")  // Char vs String range: often not what you want
+    assert( 'x' in 'a'..'z')     // OK
+    assert( "x" !in 'a'..'z')   // String in Char range: likely not intended
+    >>> void
+
+## Grouping multiple conditions with commas
+
+You can group values and/or `is`/`in` checks for a single result:
+
+    fun classify(x) {
+        when(x) {
+            "42", 42 -> "answer"
+            is Real, is Int -> "number"
+            in ['@', '#', '^'] -> "punct1"
+            in "*&.," -> "punct2"
+            else -> "unknown"
+        }
+    }
+    assertEquals("number", classify(π/2))
+    assertEquals("answer", classify(42))
+    assertEquals("answer", classify("42"))
+    >>> void
+
+## Return value and blocks
+
+- `when` returns the value of the matched branch result expression/block.
+- Branch bodies can be single expressions or blocks `{ ... }`.
+- If a matched branch produces `void` (e.g., only prints), the `when` result is `void`.
+
+    val res = when(2) {
+        1 -> 10
+        2 -> { println("two"); 20 }
+        else -> 0
+    }
+    assertEquals(20, res)
+    >>> void
+
+## Else branch
+
+- Optional but recommended when non‑exhaustive.
+- If omitted and nothing matches, `when` result is `void` (see r3 in the Quick examples).
+- Only one `else` is allowed.
+
+## Subject‑less `when`
+
+The Kotlin‑style subject‑less form `when { condition -> ... }` is not implemented yet in Lyng. Use `if/else` chains or structure your checks around a subject with `when(subject) { ... }`.
+
+## Extending `when` for your own types
+
+### Equality matches
+- Equality checks in `when(subject)` use Lyng comparison (`compareTo` semantics under the hood). For your own Lyng classes, implement comparison appropriately so that `subject == value` works as intended.
+
+### `in` / `!in` containment
+- Provide a `contains(item)` method on your class to participate in `in` conditions.
+- Example: a custom `Box` that contains one specific item:
+
+    class Box(val item)
+    fun Box.contains(x) { x == item }
+    
+    val b = Box(10)
+    when(10) { in b -> "hit" }
+    >>> "hit"
+
+Any built‑in collection (`List`, `Set`, `Array`), `Range`, `Buffer`, and other containers already implement `contains`.
+
+### Type checks (`is` / `!is`)
+- Every value has a `::class` that yields its Lyng class object, e.g. `[1,2,3]::class` → `List`.
+- `is ClassName` in `when` uses Lyng’s class hierarchy. Ensure your class is declared and can be referenced by name.
+
+    []::class == List
+    >>> true
+    
+    fun f(x) { when(x) { is List -> "list" else -> "other" } }
+    assertEquals("list", f([1]))
+    >>> void
+
+## Kotlin‑backed classes (embedding)
+
+When embedding Lyng in Kotlin, you may expose Kotlin‑backed objects and classes. Interactions inside `when` work as follows:
+- `is` checks use the Lyng class object you expose for your Kotlin type. Ensure your exposed class participates in the Lyng class hierarchy (see Embedding docs).
+- `in` checks call `contains(subject)`; if your Kotlin‑backed object wants to support `in`, expose a `contains(item)` method (mapped to Lyng) or implement the corresponding Lyng container wrapper.
+- Equality follows Lyng comparison rules. Ensure your Kotlin‑backed object’s Lyng adapter implements equality/compare correctly.
+
+For details on exposing classes/methods from Kotlin, see: [Embedding Lyng in your Kotlin project](embedding.md).
+
+## Gotchas and tips
+
+- First match wins; there is no fall‑through. Order branches carefully.
+- Group related conditions with commas for readability and performance (a single branch evaluation).
+- Prefer character ranges for character tests; avoid mixing `String` and `Char` ranges.
+- If you rely on `in`, check that your container implements `contains(item)`.
+- Remember: `when` is an expression — you can assign its result to a variable or return it from a function.
+
+## Additional examples
+
+    fun label(ch) {
+        when(ch) {
+            in '0'..'9' -> "digit"
+            in 'a'..'z', in 'A'..'Z' -> "letter"
+            '$' -> "dollar"
+            else -> "other"
+        }
+    }
+    assertEquals("digit", label('3'))
+    assertEquals("dollar", label('$'))
+    >>> void
+
+    fun normalize(x) {
+        when(x) {
+            is Int -> x
+            is Real -> x.round()
+            else -> 0
+        }
+    }
+    assertEquals(12, normalize(12))
+    assertEquals(3,  normalize(2.6))
+    >>> void

editors/lyng-textmate/README.md

@@ -0,0 +1,68 @@
+Lyng TextMate grammar
+======================
+
+This folder contains a TextMate grammar for the Lyng language so you can get syntax highlighting quickly in:
+
+- JetBrains IDEs (IntelliJ IDEA, Fleet, etc.) via “TextMate Bundles”
+- VS Code (via “Install from VSIX” or by adding as an extension folder)
+
+Files
+-----
+- `package.json` — VS Code–style wrapper that JetBrains IDEs can import as a TextMate bundle.
+- `syntaxes/lyng.tmLanguage.json` — the grammar. It highlights:
+  - Line and block comments (`//`, `/* */`)
+  - Shebang line at file start (`#!...`)
+  - Strings: single and double quotes with escapes
+  - Char literals `'x'` with escapes
+  - Numbers: decimal with underscores and exponents, and hex (`0x...`)
+  - Keywords (control and declarations), boolean operator words (`and`, `or`, `not`, `in`, `is`, `as`, `as?`)
+  - Composite textual operators: `not in`, `not is`
+  - Constants: `true`, `false`, `null`, `this`
+  - Annotations: `@name` (Unicode identifiers supported)
+  - Labels: `name:` (Unicode identifiers supported)
+  - Declarations: highlights declared names in `fun|fn name`, `class|enum Name`, `val|var name`
+  - Types: built-ins (`Int|Real|String|Bool|Char|Regex`) and Capitalized identifiers (heuristic)
+  - Operators including ranges (`..`, `..<`, `...`), null-safe (`?.`, `?[`, `?(`, `?{`, `?:`, `??`), arrows (`->`, `=>`, `::`), match operators (`=~`, `!~`), bitwise, arithmetic, etc.
+  - Shuttle operator `<=>`
+  - Division operator `/` (note: Lyng has no regex literal syntax; `/` is always division)
+  - Named arguments at call sites `name: value` (the `name` part is highlighted as `variable.parameter.named.lyng` and the `:` as punctuation). The rule is anchored to `(` or `,` and excludes `::` to avoid conflicts.
+
+Install in IntelliJ IDEA (and other JetBrains IDEs)
+---------------------------------------------------
+1. Open Settings / Preferences → Editor → TextMate Bundles.
+2. Click “+” and select this folder `editors/lyng-textmate/` (the folder that contains `package.json`).
+3. Ensure `*.lyng` is associated with the Lyng grammar (IntelliJ usually picks this up from `fileTypes`).
+4. Optional: customize colors with Settings → Editor → Color Scheme → TextMate.
+
+Enable Markdown code-fence highlighting in IntelliJ
+--------------------------------------------------
+1. Settings / Preferences → Languages & Frameworks → Markdown → Code style → Code fences → Languages.
+2. Add mapping: language id `lyng` → “Lyng (TextMate)”.
+3. Now blocks like
+   ```
+   ```lyng
+   // Lyng code here
+   ```
+   ```
+   will be highlighted.
+
+Install in VS Code
+------------------
+Fastest local install without packaging:
+1. Copy or symlink this folder somewhere stable (or keep it in your workspace).
+2. Use “Developer: Install Extension from Location…” (Insiders) or package with `vsce package` and install the resulting `.vsix`.
+3. VS Code will auto-associate `*.lyng` via this extension; if needed, check File Associations.
+
+Notes and limitations
+---------------------
+- Type highlighting is heuristic (Capitalized identifiers). The IntelliJ plugin will use language semantics and avoid false positives.
+- If your language adds or changes tokens, please update patterns in `lyng.tmLanguage.json`. The Kotlin sources in `lynglib/src/commonMain/kotlin/net/sergeych/lyng/highlight/` are a good reference for token kinds.
+- Labels `name:` at statement level remain supported and are kept distinct from named call arguments by context. The grammar prefers named-argument matching when a `name:` appears right after `(` or `,`.
+
+Lyng specifics
+--------------
+- There are no regex literal tokens in Lyng at the moment; the slash character `/` is always treated as the division operator. The grammar intentionally does not define a `/.../` regex rule to avoid mis-highlighting lines like `a / b`.
+
+Contributing
+------------
+Pull requests to refine patterns and add tests/samples are welcome. You can place test snippets in `sample_texts/` and visually verify.

editors/lyng-textmate/package.json

@@ -0,0 +1,25 @@
+{
+  "name": "lyng-textmate",
+  "displayName": "Lyng",
+  "description": "TextMate grammar for the Lyng language (for JetBrains IDEs via TextMate Bundles and VS Code).",
+  "version": "0.0.3",
+  "publisher": "lyng",
+  "license": "Apache-2.0",
+  "engines": { "vscode": "^1.0.0" },
+  "contributes": {
+    "languages": [
+      {
+        "id": "lyng",
+        "aliases": ["Lyng", "lyng"],
+        "extensions": [".lyng"]
+      }
+    ],
+    "grammars": [
+      {
+        "language": "lyng",
+        "scopeName": "source.lyng",
+        "path": "./syntaxes/lyng.tmLanguage.json"
+      }
+    ]
+  }
+}

editors/lyng-textmate/syntaxes/lyng.tmLanguage.json

@@ -0,0 +1,86 @@
+{
+  "$schema": "https://raw.githubusercontent.com/martinring/tmlanguage/master/tmlanguage.json",
+  "name": "Lyng",
+  "scopeName": "source.lyng",
+  "fileTypes": ["lyng"],
+  "patterns": [
+    { "include": "#shebang" },
+    { "include": "#comments" },
+    { "include": "#strings" },
+    { "include": "#char" },
+    { "include": "#numbers" },
+    { "include": "#declarations" },
+    { "include": "#keywords" },
+    { "include": "#constants" },
+    { "include": "#types" },
+    { "include": "#mapLiterals" },
+    { "include": "#namedArgs" },
+    { "include": "#annotations" },
+    { "include": "#labels" },
+    { "include": "#directives" },
+    { "include": "#operators" },
+    { "include": "#punctuation" }
+  ],
+  "repository": {
+    "shebang": { "patterns": [ { "name": "comment.line.shebang.lyng", "match": "^#!.*$" } ] },
+    "comments": {
+      "patterns": [
+        { "name": "comment.line.double-slash.lyng", "match": "//.*$" },
+        { "name": "comment.block.lyng", "begin": "/\\*", "end": "\\*/" }
+      ]
+    },
+    "strings": {
+      "patterns": [
+        { "name": "string.quoted.double.lyng", "begin": "\"", "end": "\"", "patterns": [ { "match": "\\\\.", "name": "constant.character.escape.lyng" } ] },
+        { "name": "string.quoted.single.lyng", "begin": "'", "end": "'", "patterns": [ { "match": "\\\\.", "name": "constant.character.escape.lyng" } ] }
+      ]
+    },
+    "char": { "patterns": [ { "name": "constant.character.lyng", "match": "'(?:[^\\\\']|\\\\.)'" } ] },
+    "numbers": {
+      "patterns": [
+        { "name": "constant.numeric.hex.lyng", "match": "0x[0-9A-Fa-f_]+" },
+        { "name": "constant.numeric.decimal.lyng", "match": "(?<![A-Za-z_])(?:[0-9][0-9_]*)\\.(?:[0-9_]+)(?:[eE][+-]?[0-9_]+)?|(?<![A-Za-z_])(?:[0-9][0-9_]*)(?:[eE][+-]?[0-9_]+)?" }
+      ]
+    },
+    "annotations": { "patterns": [ { "name": "entity.name.label.at.lyng", "match": "@[\\p{L}_][\\p{L}\\p{N}_]*:" }, { "name": "storage.modifier.annotation.lyng", "match": "@[\\p{L}_][\\p{L}\\p{N}_]*" } ] },
+    "mapLiterals": {
+      "patterns": [
+        {
+          "name": "meta.map.entry.lyng",
+          "match": "(?:(?<=\\{|,))\\s*(\"[^\"]*\"|[\\p{L}_][\\p{L}\\p{N}_]*)\\s*(:)(?!:)",
+          "captures": {
+            "1": { "name": "variable.other.property.key.lyng" },
+            "2": { "name": "punctuation.separator.colon.lyng" }
+          }
+        },
+        {
+          "name": "meta.map.spread.lyng",
+          "match": "(?:(?<=\\{|,))\\s*(\\.\\.\\.)",
+          "captures": {
+            "1": { "name": "keyword.operator.spread.lyng" }
+          }
+        }
+      ]
+    },
+    "namedArgs": {
+      "patterns": [
+        {
+          "name": "meta.argument.named.lyng",
+          "match": "(?:(?<=\\()|(?<=,))\\s*([\\p{L}_][\\p{L}\\p{N}_]*)\\s*(:)(?!:)",
+          "captures": {
+            "1": { "name": "variable.parameter.named.lyng" },
+            "2": { "name": "punctuation.separator.colon.lyng" }
+          }
+        }
+      ]
+    },
+    "labels": { "patterns": [ { "name": "entity.name.label.lyng", "match": "[\\p{L}_][\\p{L}\\p{N}_]*:" } ] },
+    "directives": { "patterns": [ { "name": "meta.directive.lyng", "match": "^\\s*#[_A-Za-z][_A-Za-z0-9]*" } ] },
+    "declarations": { "patterns": [ { "name": "meta.function.declaration.lyng", "match": "\\b(?:fun|fn)\\s+([\\p{L}_][\\p{L}\\p{N}_]*)", "captures": { "1": { "name": "entity.name.function.lyng" } } }, { "name": "meta.type.declaration.lyng", "match": "\\b(?:class|enum)\\s+([\\p{L}_][\\p{L}\\p{N}_]*)", "captures": { "1": { "name": "entity.name.type.lyng" } } }, { "name": "meta.variable.declaration.lyng", "match": "\\b(?:val|var)\\s+([\\p{L}_][\\p{L}\\p{N}_]*)", "captures": { "1": { "name": "variable.other.declaration.lyng" } } } ] },
+    "keywords": { "patterns": [ { "name": "keyword.control.lyng", "match": "\\b(?:if|else|when|while|do|for|try|catch|finally|throw|return|break|continue)\\b" }, { "name": "keyword.declaration.lyng", "match": "\\b(?:fun|fn|class|enum|val|var|import|package|constructor|property|open|extern|private|protected|static)\\b" }, { "name": "keyword.operator.word.lyng", "match": "\\bnot\\s+(?:in|is)\\b" }, { "name": "keyword.operator.word.lyng", "match": "\\b(?:and|or|not|in|is|as|as\\?)\\b" } ] },
+    "constants": { "patterns": [ { "name": "constant.language.lyng", "match": "(?:\\b(?:true|false|null|this)\\b|π)" } ] },
+    "types": { "patterns": [ { "name": "storage.type.lyng", "match": "\\b(?:Int|Real|String|Bool|Char|Regex)\\b" }, { "name": "entity.name.type.lyng", "match": "\\b[A-Z][A-Za-z0-9_]*\\b(?!\\s*\\()" } ] },
+    "operators": { "patterns": [ { "name": "keyword.operator.comparison.lyng", "match": "===|!==|==|!=|<=|>=|<|>" }, { "name": "keyword.operator.shuttle.lyng", "match": "<=>" }, { "name": "keyword.operator.arrow.lyng", "match": "=>|->|::" }, { "name": "keyword.operator.range.lyng", "match": "\\.\\.\\.|\\.\\.<|\\.\\." }, { "name": "keyword.operator.nullsafe.lyng", "match": "\\?\\.|\\?\\[|\\?\\(|\\?\\{|\\?:|\\?\\?" }, { "name": "keyword.operator.assignment.lyng", "match": "(?:\\+=|-=|\\*=|/=|%=|=)" }, { "name": "keyword.operator.logical.lyng", "match": "&&|\\|\\|" }, { "name": "keyword.operator.bitwise.lyng", "match": "<<|>>|&|\\||\\^|~" }, { "name": "keyword.operator.match.lyng", "match": "=~|!~" }, { "name": "keyword.operator.arithmetic.lyng", "match": "\\+\\+|--|[+\\-*/%]" }, { "name": "keyword.operator.other.lyng", "match": "[!?]" } ] },
+    "punctuation": { "patterns": [ { "name": "punctuation.separator.comma.lyng", "match": "," }, { "name": "punctuation.terminator.statement.lyng", "match": ";" }, { "name": "punctuation.section.block.begin.lyng", "match": "[(]{1}|[{]{1}|\\[" }, { "name": "punctuation.section.block.end.lyng", "match": "[)]{1}|[}]{1}|\\]" }, { "name": "punctuation.accessor.dot.lyng", "match": "\\." }, { "name": "punctuation.separator.colon.lyng", "match": ":" } ] }
+  }
+}

gradle.properties

@@ -1,3 +1,20 @@
+#
+# Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+#
+
 #Gradle
 org.gradle.jvmargs=-Xmx2048M -Dfile.encoding=UTF-8 -Dkotlin.daemon.jvm.options\="-Xmx2048M"
 org.gradle.caching=true
@@ -12,3 +29,9 @@ android.nonTransitiveRClass=true
 
 # other
 kotlin.native.cacheKind.linuxX64=none
+
+# Workaround: Ensure Gradle uses a JDK with `jlink` available for AGP's JDK image transform.
+# On this environment, the system JDK 21 installation lacks `jlink`, causing
+# :lynglib:androidJdkImage to fail. Point Gradle to JDK 17 which includes `jlink`.
+# This affects only the JDK Gradle runs with; Kotlin/JVM target remains compatible.
+#org.gradle.java.home=/usr/lib/jvm/java-17-openjdk-amd64

gradle/libs.versions.toml

@@ -1,13 +1,14 @@
 [versions]
 agp = "8.5.2"
 clikt = "5.0.3"
-kotlin = "2.1.21"
+kotlin = "2.2.21"
 android-minSdk = "24"
 android-compileSdk = "34"
-kotlinx-coroutines = "1.10.1"
+kotlinx-coroutines = "1.10.2"
 mp_bintools = "0.1.12"
 firebaseCrashlyticsBuildtools = "3.0.3"
 okioVersion = "3.10.2"
+compiler = "3.2.0-alpha11"
 
 [libraries]
 clikt = { module = "com.github.ajalt.clikt:clikt", version.ref = "clikt" }
@@ -19,6 +20,7 @@ mp_bintools = { module = "net.sergeych:mp_bintools", version.ref = "mp_bintools"
 firebase-crashlytics-buildtools = { group = "com.google.firebase", name = "firebase-crashlytics-buildtools", version.ref = "firebaseCrashlyticsBuildtools" }
 okio = { module = "com.squareup.okio:okio", version.ref = "okioVersion" }
 okio-fakefilesystem = { module = "com.squareup.okio:okio-fakefilesystem", version.ref = "okioVersion" }
+compiler = { group = "androidx.databinding", name = "compiler", version.ref = "compiler" }
 
 [plugins]
 androidLibrary = { id = "com.android.library", version.ref = "agp" }

gradle/wrapper/gradle-wrapper.properties

@@ -1,3 +1,20 @@
+#
+# Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+#
+
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip

gradlew

@@ -1,13 +1,13 @@
 #!/bin/sh
 
 #
-# Copyright © 2015-2021 the original authors.
+# Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
-#      https://www.apache.org/licenses/LICENSE-2.0
+#     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
@@ -15,6 +15,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+#
 
 ##############################################################################
 #

happy.py

@@ -1,11 +0,0 @@
-count = 0
-for n1 in range(10):
-    for n2 in range(10):
-        for n3 in range(10):
-            for n4 in range(10):
-                for n5 in range(10):
-                    for n6 in range(10):
-                        if n1 + n2 + n3 == n4 + n5 + n6:
-                            count += 1
-
-print(count)

library/build.gradle.kts

@@ -1,173 +0,0 @@
-import com.codingfeline.buildkonfig.compiler.FieldSpec.Type.STRING
-import com.vanniktech.maven.publish.SonatypeHost
-import org.jetbrains.kotlin.gradle.ExperimentalKotlinGradlePluginApi
-import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
-import org.jetbrains.kotlin.gradle.dsl.JvmTarget
-
-group = "net.sergeych"
-version = "0.5.1-SNAPSHOT"
-
-buildscript {
-    repositories {
-        mavenCentral()
-    }
-    dependencies {
-        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.0")
-        classpath("com.codingfeline.buildkonfig:buildkonfig-gradle-plugin:latest_version")
-    }
-}
-
-plugins {
-    alias(libs.plugins.kotlinMultiplatform)
-    alias(libs.plugins.androidLibrary)
-    alias(libs.plugins.vanniktech.mavenPublish)
-    kotlin("plugin.serialization") version "2.1.20"
-    id("com.codingfeline.buildkonfig") version "0.17.1"
-}
-
-buildkonfig {
-    packageName = "net.sergeych.lyng"
-    // objectName = "YourAwesomeConfig"
-    // exposeObjectWithName = "YourAwesomePublicConfig"
-
-    defaultConfigs {
-        buildConfigField(STRING, "bcprovider", "codingfeline")
-        buildConfigField(STRING, "version", version.toString())
-    }
-}
-
-kotlin {
-    jvm()
-    androidTarget {
-        publishLibraryVariants("release")
-        @OptIn(ExperimentalKotlinGradlePluginApi::class)
-        compilerOptions {
-            jvmTarget.set(JvmTarget.JVM_11)
-        }
-    }
-//    iosX64()
-//    iosArm64()
-//    iosSimulatorArm64()
-    linuxX64()
-    js {
-        browser()
-        nodejs()
-    }
-    @OptIn(ExperimentalWasmDsl::class)
-    wasmJs() {
-        browser()
-        nodejs()
-    }
-
-    sourceSets {
-        all {
-            languageSettings.optIn("kotlinx.coroutines.ExperimentalCoroutinesApi")
-            languageSettings.optIn("kotlin.contracts.ExperimentalContracts::class")
-            languageSettings.optIn("kotlin.ExperimentalUnsignedTypes")
-            languageSettings.optIn("kotlin.coroutines.DelicateCoroutinesApi")
-        }
-
-        val commonMain by getting {
-            kotlin.srcDir("$buildDir/generated/buildConfig/commonMain/kotlin")
-            dependencies {
-                implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.8.1")
-                //put your multiplatform dependencies here
-                api(libs.kotlinx.coroutines.core)
-                api(libs.mp.bintools)
-                api("net.sergeych:mp_stools:1.5.2")
-            }
-        }
-        val commonTest by getting {
-            dependencies {
-                implementation(libs.kotlin.test)
-                implementation(libs.kotlinx.coroutines.test)
-            }
-        }
-    }
-}
-
-android {
-    namespace = "org.jetbrains.kotlinx.multiplatform.library.template"
-    compileSdk = libs.versions.android.compileSdk.get().toInt()
-    defaultConfig {
-        minSdk = libs.versions.android.minSdk.get().toInt()
-    }
-    compileOptions {
-        sourceCompatibility = JavaVersion.VERSION_11
-        targetCompatibility = JavaVersion.VERSION_11
-    }
-}
-dependencies {
-    implementation(libs.firebase.crashlytics.buildtools)
-}
-
-mavenPublishing {
-    publishToMavenCentral(SonatypeHost.CENTRAL_PORTAL)
-
-    signAllPublications()
-
-    coordinates(group.toString(), "library", version.toString())
-
-    pom {
-        name = "Lyng language"
-        description = "Kotlin-bound scripting loanguage"
-        inceptionYear = "2025"
-//        url = "https://sergeych.net"
-        licenses {
-            license {
-                name = "XXX"
-                url = "YYY"
-                distribution = "ZZZ"
-            }
-        }
-        developers {
-            developer {
-                id = "XXX"
-                name = "YYY"
-                url = "ZZZ"
-            }
-        }
-        scm {
-            url = "XXX"
-            connection = "YYY"
-            developerConnection = "ZZZ"
-        }
-    }
-}
-//
-//val projectVersion  by project.extra(provider {
-//    // Compute value lazily
-//    (version as String)
-//})
-//
-//val generateBuildConfig by tasks.registering {
-//    // Declare outputs safely
-//    val outputDir = layout.buildDirectory.dir("generated/buildConfig/commonMain/kotlin")
-//    outputs.dir(outputDir)
-//
-//    val version = projectVersion.get()
-//
-//    // Inputs: Version is tracked as an input
-//    inputs.property("version", version)
-//
-//    doLast {
-//        val packageName = "net.sergeych.lyng.buildconfig"
-//        val packagePath = packageName.replace('.', '/')
-//        val buildConfigFile = outputDir.get().file("$packagePath/BuildConfig.kt").asFile
-//
-//        buildConfigFile.parentFile?.mkdirs()
-//        buildConfigFile.writeText(
-//            """
-//            |package $packageName
-//            |
-//            |object BuildConfig {
-//            |    const val VERSION = "$version"
-//            |}
-//            """.trimMargin()
-//        )
-//    }
-//}
-//
-//tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach {
-//    dependsOn(generateBuildConfig)
-//}

library/src/commonMain/kotlin/net/sergeych/lyng/AccessType.kt

@@ -1,8 +0,0 @@
-package net.sergeych.lyng
-
-enum class AccessType(val isMutable: Boolean) {
-    Val(false), Var(true),
-
-    @Suppress("unused")
-    Initialization(false)
-}

library/src/commonMain/kotlin/net/sergeych/lyng/ArgsDeclaration.kt

@@ -1,124 +0,0 @@
-package net.sergeych.lyng
-
-/**
- * List of argument declarations in the __definition__ of the lambda, class constructor,
- * function, etc. It is created by [Compiler.parseArgsDeclaration]
- */
-data class ArgsDeclaration(val params: List<Item>, val endTokenType: Token.Type) {
-    init {
-        val i = params.count { it.isEllipsis }
-        if (i > 1) throw ScriptError(params[i].pos, "there can be only one argument")
-        val start = params.indexOfFirst { it.defaultValue != null }
-        if (start >= 0)
-            for (j in start + 1 until params.size)
-                // last non-default could be lambda:
-                if (params[j].defaultValue == null && j != params.size - 1) throw ScriptError(
-                    params[j].pos,
-                    "required argument can't follow default one"
-                )
-    }
-
-    /**
-     * parse args and create local vars in a given context
-     */
-    suspend fun assignToContext(
-        context: Context,
-        arguments: Arguments = context.args,
-        defaultAccessType: AccessType = AccessType.Var,
-        defaultVisibility: Visibility = Visibility.Public
-    ) {
-        fun assign(a: Item, value: Obj) {
-            context.addItem(a.name, (a.accessType ?: defaultAccessType).isMutable, value,
-                a.visibility ?: defaultVisibility)
-        }
-
-        // will be used with last lambda arg fix
-        val callArgs: List<Obj>
-        val paramsSize: Int
-
-        if( arguments.tailBlockMode ) {
-            paramsSize = params.size - 1
-            assign(params.last(), arguments.list.last())
-            callArgs = arguments.list.dropLast(1)
-        } else {
-            paramsSize = params.size
-            callArgs = arguments.list
-        }
-
-        suspend fun processHead(index: Int): Int {
-            var i = index
-            while (i != paramsSize) {
-                val a = params[i]
-                if (a.isEllipsis) break
-                val value = when {
-                    i < callArgs.size -> callArgs[i]
-                    a.defaultValue != null -> a.defaultValue.execute(context)
-                    else -> {
-                        println("callArgs: ${callArgs.joinToString()}")
-                        println("tailBlockMode: ${arguments.tailBlockMode}")
-                        context.raiseArgumentError("too few arguments for the call")
-                    }
-                }
-                assign(a, value)
-                i++
-            }
-            return i
-        }
-
-        suspend fun processTail(index: Int): Int {
-            var i = paramsSize - 1
-            var j = callArgs.size - 1
-            while (i > index) {
-                val a = params[i]
-                if (a.isEllipsis) break
-                val value = when {
-                    j >= index -> {
-                        callArgs[j--]
-                    }
-
-                    a.defaultValue != null -> a.defaultValue.execute(context)
-                    else -> context.raiseArgumentError("too few arguments for the call")
-                }
-                assign(a, value)
-                i--
-            }
-            return j
-        }
-
-        fun processEllipsis(index: Int, toFromIndex: Int) {
-            val a = params[index]
-            val l = if (index > toFromIndex) ObjList()
-            else ObjList(callArgs.subList(index, toFromIndex + 1).toMutableList())
-            assign(a, l)
-        }
-
-        val leftIndex = processHead(0)
-        if (leftIndex < paramsSize) {
-            val end = processTail(leftIndex)
-            processEllipsis(leftIndex, end)
-        } else {
-            if (leftIndex < callArgs.size)
-                context.raiseArgumentError("too many arguments for the call")
-        }
-    }
-
-    /**
-     * Single argument declaration descriptor.
-     *
-     * @param defaultValue default value, if set, can't be an [Obj] as it can depend on the call site, call args, etc.
-     *      If not null, could be executed on __caller context__ only.
-     */
-    data class Item(
-        val name: String,
-        val type: TypeDecl = TypeDecl.Obj,
-        val pos: Pos = Pos.builtIn,
-        val isEllipsis: Boolean = false,
-        /**
-         * Default value, if set, can't be an [Obj] as it can depend on the call site, call args, etc.
-         * So it is a [Statement] that must be executed on __caller context__.
-         */
-        val defaultValue: Statement? = null,
-        val accessType: AccessType? = null,
-        val visibility: Visibility? = null,
-    )
-}

library/src/commonMain/kotlin/net/sergeych/lyng/Arguments.kt

@@ -1,41 +0,0 @@
-package net.sergeych.lyng
-
-data class ParsedArgument(val value: Statement, val pos: Pos, val isSplat: Boolean = false)
-
-suspend fun Collection<ParsedArgument>.toArguments(context: Context,tailBlockMode: Boolean): Arguments {
-    val list = mutableListOf<Obj>()
-
-    for (x in this) {
-        val value = x.value.execute(context)
-        if (x.isSplat) {
-            when {
-                value is ObjList -> {
-                    for (subitem in value.list) list.add(subitem)
-                }
-
-                value.isInstanceOf(ObjIterable) -> {
-                    val i = (value.invokeInstanceMethod(context, "toList") as ObjList).list
-                    i.forEach { list.add(it) }
-                }
-
-                else -> context.raiseClassCastError("expected list of objects for splat argument")
-            }
-        } else
-            list.add(value)
-    }
-    return Arguments(list,tailBlockMode)
-}
-
-data class Arguments(val list: List<Obj>,val tailBlockMode: Boolean = false) : List<Obj> by list {
-
-    fun firstAndOnly(pos: Pos = Pos.UNKNOWN): Obj {
-        if (list.size != 1) throw ScriptError(pos, "expected one argument, got ${list.size}")
-        return list.first()
-    }
-
-    companion object {
-        val EMPTY = Arguments(emptyList())
-        fun from(values: Collection<Obj>) = Arguments(values.toList())
-    }
-}
-

library/src/commonMain/kotlin/net/sergeych/lyng/BuildDoubleFromParts.kt

@@ -1,19 +0,0 @@
-package net.sergeych.lyng
-
-//fun buildDoubleFromParts(
-//    integerPart: Long,
-//    decimalPart: Long,
-//    exponent: Int
-//): Double {
-//    // Handle zero decimal case efficiently
-//    val numDecimalDigits = if (decimalPart == 0L) 0 else decimalPart.toString().length
-//
-//    // Calculate decimal multiplier (10^-digits)
-//    val decimalMultiplier = 10.0.pow(-numDecimalDigits)
-//
-//    // Combine integer and decimal parts
-//    val baseValue = integerPart.toDouble() + decimalPart.toDouble() * decimalMultiplier
-//
-//    // Apply exponent
-//    return baseValue * 10.0.pow(exponent)
-//}

library/src/commonMain/kotlin/net/sergeych/lyng/CompilerContext.kt

@@ -1,152 +0,0 @@
-package net.sergeych.lyng
-
-internal class CompilerContext(val tokens: List<Token>) {
-    val labels = mutableSetOf<String>()
-
-    var breakFound = false
-        private set
-
-    var loopLevel = 0
-        private set
-
-    inline fun <T> parseLoop(f: () -> T): Pair<Boolean, T> {
-        if (++loopLevel == 0) breakFound = false
-        val result = f()
-        return Pair(breakFound, result).also {
-            --loopLevel
-        }
-    }
-
-    var currentIndex = 0
-
-    fun hasNext() = currentIndex < tokens.size
-    fun hasPrevious() = currentIndex > 0
-    fun next() = tokens.getOrElse(currentIndex) { throw IllegalStateException("No next token") }.also { currentIndex++ }
-    fun previous() = if (!hasPrevious()) throw IllegalStateException("No previous token") else tokens[--currentIndex]
-
-    fun savePos() = currentIndex
-    fun restorePos(pos: Int) {
-        currentIndex = pos
-    }
-
-    fun ensureLabelIsValid(pos: Pos, label: String) {
-        if (label !in labels)
-            throw ScriptError(pos, "Undefined label '$label'")
-    }
-
-    @Suppress("unused")
-    fun requireId() = requireToken(Token.Type.ID, "identifier is required")
-
-    fun requireToken(type: Token.Type, message: String = "required ${type.name}"): Token =
-        next().also {
-            if (type != it.type) throw ScriptError(it.pos, message)
-        }
-
-    @Suppress("unused")
-    fun syntaxError(at: Pos, message: String = "Syntax error"): Nothing {
-        throw ScriptError(at, message)
-    }
-
-    fun currentPos() =
-        if (hasNext()) next().pos.also { previous() }
-        else previous().pos.also { next() }
-
-    /**
-     * Skips next token if its type is `tokenType`, returns `true` if so.
-     * @param errorMessage message to throw if next token is not `tokenType`
-     * @param isOptional if `true` and token is not of `tokenType`, just return `false` and does not skip it
-     * @return `true` if the token was skipped
-     * @throws ScriptError if [isOptional] is `false` and next token is not of [tokenType]
-     */
-    fun skipTokenOfType(
-        tokenType: Token.Type,
-        errorMessage: String = "expected ${tokenType.name}",
-        isOptional: Boolean = false
-    ): Boolean {
-        val t = next()
-        return if (t.type != tokenType) {
-            if (!isOptional) {
-                println("unexpected: $t (needed $tokenType)")
-                throw ScriptError(t.pos, errorMessage)
-            } else {
-                previous()
-                false
-            }
-        } else true
-    }
-
-    @Suppress("unused")
-    fun skipTokens(vararg tokenTypes: Token.Type) {
-        while (next().type in tokenTypes) { /**/
-        }
-        previous()
-    }
-
-
-    fun ifNextIs(typeId: Token.Type, f: (Token) -> Unit): Boolean {
-        val t = next()
-        return if (t.type == typeId) {
-            f(t)
-            true
-        } else {
-            previous()
-            false
-        }
-    }
-
-    inline fun addBreak() {
-        breakFound = true
-    }
-
-    /**
-     * Return value of the next token if it is an identifier, null otherwise.
-     * Does not change position.
-     */
-    fun nextIdValue(): String? {
-        return if (hasNext()) {
-            val nt = tokens[currentIndex]
-            if (nt.type == Token.Type.ID)
-                nt.value
-            else null
-        } else null
-    }
-
-    @Suppress("unused")
-    fun current(): Token = tokens[currentIndex]
-
-    /**
-     * If the token at current position plus offset (could be negative) exists, returns it, otherwise returns null.
-     */
-    fun atOffset(offset: Int): Token? =
-        if (currentIndex + offset in tokens.indices) tokens[currentIndex + offset] else null
-
-    /**
-     * Scan backwards as deep as specified looking for visibility token. Does not change position.
-     */
-    fun getVisibility(default: Visibility = Visibility.Public, depths: Int = 2): Visibility {
-        for( i in -depths .. -1) {
-            when( atOffset(i)?.type) {
-                Token.Type.PROTECTED -> return Visibility.Protected
-                Token.Type.PRIVATE -> return Visibility.Private
-                else -> {}
-            }
-        }
-        return default
-    }
-
-//    fun expectKeyword(vararg keyword: String): String {
-//        val t = next()
-//        if (t.type != Token.Type.ID && t.value !in keyword) {
-//            throw ScriptError(t.pos, "expected one of ${keyword.joinToString()}")
-//
-//    }
-
-//    data class ReturnScope(val needCatch: Boolean = false)
-
-//    private val
-
-//    fun startReturnScope(): ReturnScope {
-//        return ReturnScope()
-//    }
-
-}

library/src/commonMain/kotlin/net/sergeych/lyng/Context.kt

@@ -1,123 +0,0 @@
-package net.sergeych.lyng
-
-class Context(
-    val parent: Context?,
-    val args: Arguments = Arguments.EMPTY,
-    var pos: Pos = Pos.builtIn,
-    val thisObj: Obj = ObjVoid,
-    var skipContextCreation: Boolean = false,
-) {
-    constructor(
-        args: Arguments = Arguments.EMPTY,
-        pos: Pos = Pos.builtIn,
-    )
-            : this(Script.defaultContext, args, pos)
-
-    fun raiseNotImplemented(what: String = "operation"): Nothing = raiseError("$what is not implemented")
-
-    @Suppress("unused")
-    fun raiseNPE(): Nothing = raiseError(ObjNullPointerException(this))
-
-    @Suppress("unused")
-    fun raiseIndexOutOfBounds(message: String = "Index out of bounds"): Nothing =
-        raiseError(ObjIndexOutOfBoundsException(this, message))
-
-    @Suppress("unused")
-    fun raiseArgumentError(message: String = "Illegal argument error"): Nothing =
-        raiseError(ObjIllegalArgumentException(this, message))
-
-    fun raiseClassCastError(msg: String): Nothing = raiseError(ObjClassCastException(this, msg))
-
-    @Suppress("unused")
-    fun raiseSymbolNotFound(name: String): Nothing =
-        raiseError(ObjSymbolNotDefinedException(this, "symbol is not defined: $name"))
-
-    fun raiseError(message: String): Nothing {
-        throw ExecutionError(ObjException(this, message))
-    }
-
-    fun raiseError(obj: ObjException): Nothing {
-        throw ExecutionError(obj)
-    }
-
-    inline fun <reified T : Obj> requiredArg(index: Int): T {
-        if (args.list.size <= index) raiseError("Expected at least ${index + 1} argument, got ${args.list.size}")
-        return (args.list[index] as? T)
-            ?: raiseClassCastError("Expected type ${T::class.simpleName}, got ${args.list[index]::class.simpleName}")
-    }
-
-    inline fun <reified T : Obj> requireOnlyArg(): T {
-        if (args.list.size != 1) raiseError("Expected exactly 1 argument, got ${args.list.size}")
-        return requiredArg(0)
-    }
-
-    @Suppress("unused")
-    fun requireExactCount(count: Int) {
-        if (args.list.size != count) {
-            raiseError("Expected exactly $count arguments, got ${args.list.size}")
-        }
-    }
-
-    inline fun <reified T : Obj> thisAs(): T = (thisObj as? T)
-        ?: raiseClassCastError("Cannot cast ${thisObj.objClass.className} to ${T::class.simpleName}")
-
-    internal val objects = mutableMapOf<String, ObjRecord>()
-
-    operator fun get(name: String): ObjRecord? =
-        objects[name]
-            ?: parent?.get(name)
-
-    fun copy(pos: Pos, args: Arguments = Arguments.EMPTY, newThisObj: Obj? = null): Context =
-        Context(this, args, pos, newThisObj ?: thisObj)
-
-    fun copy(args: Arguments = Arguments.EMPTY, newThisObj: Obj? = null): Context =
-        Context(this, args, pos, newThisObj ?: thisObj)
-
-    fun copy() = Context(this, args, pos, thisObj)
-
-    fun addItem(
-        name: String,
-        isMutable: Boolean,
-        value: Obj,
-        visibility: Visibility = Visibility.Public
-    ): ObjRecord {
-        return ObjRecord(value, isMutable, visibility).also { objects[name] = it }
-    }
-
-    fun getOrCreateNamespace(name: String): ObjClass {
-        val ns = objects.getOrPut(name) { ObjRecord(ObjNamespace(name), isMutable = false) }.value
-        return ns.objClass
-    }
-
-    inline fun addVoidFn(vararg names: String, crossinline fn: suspend Context.() -> Unit) {
-        addFn<ObjVoid>(*names) {
-            fn(this)
-            ObjVoid
-        }
-    }
-
-    inline fun <reified T : Obj> addFn(vararg names: String, crossinline fn: suspend Context.() -> T) {
-        val newFn = object : Statement() {
-            override val pos: Pos = Pos.builtIn
-
-            override suspend fun execute(context: Context): Obj = context.fn()
-
-        }
-        for (name in names) {
-            addItem(
-                name,
-                false,
-                newFn
-            )
-        }
-    }
-
-    fun addConst(name: String, value: Obj) = addItem(name, false, value)
-
-    suspend fun eval(code: String): Obj =
-        Compiler().compile(code.toSource()).execute(this)
-
-    fun containsLocal(name: String): Boolean = name in objects
-
-
-}

library/src/commonMain/kotlin/net/sergeych/lyng/ListEntry.kt

@@ -1,7 +0,0 @@
-package net.sergeych.lyng
-
-sealed class ListEntry {
-    data class Element(val accessor: Accessor) : ListEntry()
-
-    data class Spread(val accessor: Accessor) : ListEntry()
-}

library/src/commonMain/kotlin/net/sergeych/lyng/LoopBreakContinueException.kt

@@ -1,7 +0,0 @@
-package net.sergeych.lyng
-
-class LoopBreakContinueException(
-    val doContinue: Boolean,
-    val result: Obj = ObjVoid,
-    val label: String? = null
-) : RuntimeException()

library/src/commonMain/kotlin/net/sergeych/lyng/Obj.kt

@@ -1,428 +0,0 @@
-package net.sergeych.lyng
-
-import kotlinx.coroutines.sync.Mutex
-import kotlinx.coroutines.sync.withLock
-import kotlinx.serialization.SerialName
-import kotlinx.serialization.Serializable
-import net.sergeych.bintools.encodeToHex
-import net.sergeych.synctools.ProtectedOp
-import net.sergeych.synctools.withLock
-import kotlin.contracts.ExperimentalContracts
-
-/**
- * Record to store object with access rules, e.g. [isMutable] and access level [visibility].
- */
-data class ObjRecord(
-    var value: Obj,
-    val isMutable: Boolean,
-    val visibility: Visibility = Visibility.Public
-)
-
-/**
- * When we need read-write access to an object in some abstract storage, we need Accessor,
- * as in-site assigning is not always sufficient, in general case we need to replace the object
- * in the storage.
- *
- * Note that assigning new value is more complex than just replacing the object, see how assignment
- * operator is implemented in [Compiler.allOps].
- */
-data class Accessor(
-    val getter: suspend (Context) -> ObjRecord,
-    val setterOrNull: (suspend (Context, Obj) -> Unit)?
-) {
-    /**
-     * Simplified constructor for immutable stores.
-     */
-    constructor(getter: suspend (Context) -> ObjRecord) : this(getter, null)
-
-    /**
-     * Get the setter or throw.
-     */
-    fun setter(pos: Pos) = setterOrNull ?: throw ScriptError(pos, "can't assign value")
-}
-
-open class Obj {
-    var isFrozen: Boolean = false
-
-    private val monitor = Mutex()
-
-    //    private val memberMutex = Mutex()
-    internal var parentInstances: MutableList<Obj> = mutableListOf()
-
-    private val opInstances = ProtectedOp()
-
-    open fun inspect(): String = toString()
-
-    /**
-     * Some objects are by-value, historically [ObjInt] and [ObjReal] are usually treated as such.
-     * When initializing a var with it, by value objects must be copied. By-reference ones aren't.
-     *
-     * Almost all objects are by-reference.
-     */
-    open fun byValueCopy(): Obj = this
-
-    fun isInstanceOf(someClass: Obj) = someClass === objClass || objClass.allParentsSet.contains(someClass)
-
-    suspend fun invokeInstanceMethod(context: Context, name: String, vararg args: Obj): Obj =
-        invokeInstanceMethod(context, name, Arguments(args.toList()))
-
-    suspend inline fun <reified T : Obj> callMethod(
-        context: Context,
-        name: String,
-        args: Arguments = Arguments.EMPTY
-    ): T = invokeInstanceMethod(context, name, args) as T
-
-    open suspend fun invokeInstanceMethod(
-        context: Context,
-        name: String,
-        args: Arguments = Arguments.EMPTY
-    ): Obj =
-        // note that getInstanceMember traverses the hierarchy
-        objClass.getInstanceMember(context.pos, name).value.invoke(context, this, args)
-
-    fun getMemberOrNull(name: String): Obj? = objClass.getInstanceMemberOrNull(name)?.value
-
-    // methods that to override
-
-    open suspend fun compareTo(context: Context, other: Obj): Int {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun contains(context: Context, other: Obj): Boolean {
-        context.raiseNotImplemented()
-    }
-
-    open val asStr: ObjString by lazy {
-        if (this is ObjString) this else ObjString(this.toString())
-    }
-
-    /**
-     * Class of the object: definition of member functions (top-level), etc.
-     * Note that using lazy allows to avoid endless recursion here
-     */
-    open val objClass: ObjClass by lazy {
-        ObjClass("Obj").apply {
-            addFn("toString") {
-                thisObj.asStr
-            }
-            addFn("contains") {
-                ObjBool(thisObj.contains(this, args.firstAndOnly()))
-            }
-        }
-    }
-
-    open suspend fun plus(context: Context, other: Obj): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun minus(context: Context, other: Obj): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun mul(context: Context, other: Obj): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun div(context: Context, other: Obj): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun mod(context: Context, other: Obj): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun logicalNot(context: Context): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun logicalAnd(context: Context, other: Obj): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun logicalOr(context: Context, other: Obj): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun assign(context: Context, other: Obj): Obj? = null
-
-    /**
-     * a += b
-     * if( the operation is not defined, it returns null and the compiler would try
-     * to generate it as 'this = this + other', reassigning its variable
-     */
-    open suspend fun plusAssign(context: Context, other: Obj): Obj? = null
-
-    /**
-     * `-=` operations, see [plusAssign]
-     */
-    open suspend fun minusAssign(context: Context, other: Obj): Obj? = null
-    open suspend fun mulAssign(context: Context, other: Obj): Obj? = null
-    open suspend fun divAssign(context: Context, other: Obj): Obj? = null
-    open suspend fun modAssign(context: Context, other: Obj): Obj? = null
-
-    open suspend fun getAndIncrement(context: Context): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun incrementAndGet(context: Context): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun decrementAndGet(context: Context): Obj {
-        context.raiseNotImplemented()
-    }
-
-    open suspend fun getAndDecrement(context: Context): Obj {
-        context.raiseNotImplemented()
-    }
-
-    fun willMutate(context: Context) {
-        if (isFrozen) context.raiseError("attempt to mutate frozen object")
-    }
-
-    suspend fun <T> sync(block: () -> T): T = monitor.withLock { block() }
-
-    open suspend fun readField(context: Context, name: String): ObjRecord {
-        // could be property or class field:
-        val obj = objClass.getInstanceMemberOrNull(name) ?: context.raiseError("no such field: $name")
-        return when (val value = obj.value) {
-            is Statement -> {
-                ObjRecord(value.execute(context.copy(context.pos, newThisObj = this)), obj.isMutable)
-            }
-            // could be writable property naturally
-//            null -> ObjNull.asReadonly
-            else -> obj
-        }
-    }
-
-    open suspend fun writeField(context: Context, name: String, newValue: Obj) {
-        willMutate(context)
-        val field = objClass.getInstanceMemberOrNull(name) ?: context.raiseError("no such field: $name")
-        if (field.isMutable) field.value = newValue else context.raiseError("can't assign to read-only field: $name")
-    }
-
-    open suspend fun getAt(context: Context, index: Int): Obj {
-        context.raiseNotImplemented("indexing")
-    }
-
-    open suspend fun putAt(context: Context, index: Int, newValue: Obj) {
-        context.raiseNotImplemented("indexing")
-    }
-
-    open suspend fun callOn(context: Context): Obj {
-        context.raiseNotImplemented()
-    }
-
-    suspend fun invoke(context: Context, thisObj: Obj, args: Arguments): Obj =
-        callOn(context.copy(context.pos, args = args, newThisObj = thisObj))
-
-    suspend fun invoke(context: Context, thisObj: Obj, vararg args: Obj): Obj =
-        callOn(
-            context.copy(
-                context.pos,
-                args = Arguments(args.toList()),
-                newThisObj = thisObj
-            )
-        )
-
-    suspend fun invoke(context: Context, thisObj: Obj): Obj =
-        callOn(
-            context.copy(
-                context.pos,
-                args = Arguments.EMPTY,
-                newThisObj = thisObj
-            )
-        )
-
-    suspend fun invoke(context: Context, atPos: Pos, thisObj: Obj, args: Arguments): Obj =
-        callOn(context.copy(atPos, args = args, newThisObj = thisObj))
-
-
-    val asReadonly: ObjRecord by lazy { ObjRecord(this, false) }
-    val asMutable: ObjRecord by lazy { ObjRecord(this, true) }
-
-
-    companion object {
-        inline fun <reified T> from(obj: T): Obj {
-            return when (obj) {
-                is Obj -> obj
-                is Double -> ObjReal(obj)
-                is Float -> ObjReal(obj.toDouble())
-                is Int -> ObjInt(obj.toLong())
-                is Long -> ObjInt(obj)
-                is String -> ObjString(obj)
-                is CharSequence -> ObjString(obj.toString())
-                is Boolean -> ObjBool(obj)
-                Unit -> ObjVoid
-                null -> ObjNull
-                else -> throw IllegalArgumentException("cannot convert to Obj: $obj")
-            }
-        }
-    }
-}
-
-@Suppress("unused")
-inline fun <reified T> T.toObj(): Obj = Obj.from(this)
-
-@Serializable
-@SerialName("void")
-object ObjVoid : Obj() {
-    override fun equals(other: Any?): Boolean {
-        return other is ObjVoid || other is Unit
-    }
-
-    override suspend fun compareTo(context: Context, other: Obj): Int {
-        return if (other === this) 0 else -1
-    }
-
-    override fun toString(): String = "void"
-}
-
-@Serializable
-@SerialName("null")
-object ObjNull : Obj() {
-    override suspend fun compareTo(context: Context, other: Obj): Int {
-        return if (other === this) 0 else -1
-    }
-
-    override fun equals(other: Any?): Boolean {
-        return other is ObjNull || other == null
-    }
-
-    override fun toString(): String = "null"
-}
-
-interface Numeric {
-    val longValue: Long
-    val doubleValue: Double
-    val toObjInt: ObjInt
-    val toObjReal: ObjReal
-}
-
-fun Obj.toDouble(): Double =
-    (this as? Numeric)?.doubleValue
-        ?: (this as? ObjString)?.value?.toDouble()
-        ?: throw IllegalArgumentException("cannot convert to double $this")
-
-@Suppress("unused")
-fun Obj.toLong(): Long =
-    when (this) {
-        is Numeric -> longValue
-        is ObjString -> value.toLong()
-        is ObjChar -> value.code.toLong()
-        else -> throw IllegalArgumentException("cannot convert to double $this")
-    }
-
-fun Obj.toInt(): Int = toLong().toInt()
-
-fun Obj.toBool(): Boolean =
-    (this as? ObjBool)?.value ?: throw IllegalArgumentException("cannot convert to boolean $this")
-
-
-data class ObjNamespace(val name: String) : Obj() {
-    override val objClass by lazy { ObjClass(name) }
-
-    override fun inspect(): String = "Ns[$name]"
-
-    override fun toString(): String {
-        return "package $name"
-    }
-}
-
-open class ObjException(exceptionClass: ExceptionClass, val context: Context, val message: String) : Obj() {
-    constructor(name: String,context: Context, message: String) : this(getOrCreateExceptionClass(name), context, message)
-    constructor(context: Context, message: String) : this(Root, context, message)
-
-    fun raise(): Nothing {
-        throw ExecutionError(this)
-    }
-
-    override val objClass: ObjClass = exceptionClass
-
-    override fun toString(): String {
-        return "ObjException:${objClass.className}:${context.pos}@${hashCode().encodeToHex()}"
-    }
-
-    companion object {
-
-        class ExceptionClass(val name: String,vararg parents: ObjClass) : ObjClass(name, *parents) {
-            override suspend fun callOn(context: Context): Obj {
-                val message = context.args.getOrNull(0)?.toString() ?: name
-                return ObjException(this, context, message)
-            }
-            override fun toString(): String = "ExceptionClass[$name]@${hashCode().encodeToHex()}"
-        }
-        val Root = ExceptionClass("Throwable").apply {
-            addConst("message", statement {
-                (thisObj as ObjException).message.toObj()
-            })
-        }
-
-        private val op = ProtectedOp()
-        private val existingErrorClasses = mutableMapOf<String, ExceptionClass>()
-
-
-        @OptIn(ExperimentalContracts::class)
-        protected fun getOrCreateExceptionClass(name: String): ExceptionClass {
-            return op.withLock {
-                existingErrorClasses.getOrPut(name) {
-                    ExceptionClass(name, Root)
-                }
-            }
-        }
-
-        /**
-         * Get [ObjClass] for error class by name if exists.
-         */
-        @OptIn(ExperimentalContracts::class)
-        fun getErrorClass(name: String): ObjClass? = op.withLock {
-            existingErrorClasses[name]
-        }
-
-        fun addExceptionsToContext(context: Context) {
-            context.addConst("Exception", Root)
-            existingErrorClasses["Exception"] = Root
-            for (name in listOf(
-                "NullPointerException",
-                "AssertionFailedException",
-                "ClassCastException",
-                "IndexOutOfBoundsException",
-                "IllegalArgumentException",
-                "IllegalAssignmentException",
-                "SymbolNotDefinedException",
-                "IterationEndException",
-                "AccessException",
-                "UnknownException",
-            )) {
-                context.addConst(name, getOrCreateExceptionClass(name))
-            }
-        }
-    }
-}
-
-class ObjNullPointerException(context: Context) : ObjException("NullPointerException", context, "object is null")
-
-class ObjAssertionFailedException(context: Context, message: String) :
-    ObjException("AssertionFailedException", context, message)
-
-class ObjClassCastException(context: Context, message: String) : ObjException("ClassCastException", context, message)
-class ObjIndexOutOfBoundsException(context: Context, message: String = "index out of bounds") :
-    ObjException("IndexOutOfBoundsException", context, message)
-
-class ObjIllegalArgumentException(context: Context, message: String = "illegal argument") :
-    ObjException("IllegalArgumentException", context, message)
-
-class ObjIllegalAssignmentException(context: Context, message: String = "illegal assignment") :
-    ObjException("IllegalAssignmentException", context, message)
-
-class ObjSymbolNotDefinedException(context: Context, message: String = "symbol is not defined") :
-    ObjException("SymbolNotDefinedException", context, message)
-
-class ObjIterationFinishedException(context: Context) :
-    ObjException("IterationEndException", context, "iteration finished")
-
-class ObjAccessException(context: Context, message: String = "access not allowed error") :
-    ObjException("AccessException", context, message)
-
-class ObjUnknownException(context: Context, message: String = "access not allowed error") :
-    ObjException("UnknownException", context, message)

library/src/commonMain/kotlin/net/sergeych/lyng/ObjBool.kt

@@ -1,27 +0,0 @@
-package net.sergeych.lyng
-
-data class ObjBool(val value: Boolean) : Obj() {
-    override val asStr by lazy { ObjString(value.toString()) }
-
-    override suspend fun compareTo(context: Context, other: Obj): Int {
-        if (other !is ObjBool) return -2
-        return value.compareTo(other.value)
-    }
-
-    override fun toString(): String = value.toString()
-
-    override val objClass: ObjClass = type
-
-    override suspend fun logicalNot(context: Context): Obj = ObjBool(!value)
-
-    override suspend fun logicalAnd(context: Context, other: Obj): Obj = ObjBool(value && other.toBool())
-
-    override suspend fun logicalOr(context: Context, other: Obj): Obj = ObjBool(value || other.toBool())
-
-    companion object {
-        val type = ObjClass("Bool")
-    }
-}
-
-val ObjTrue = ObjBool(true)
-val ObjFalse = ObjBool(false)

library/src/commonMain/kotlin/net/sergeych/lyng/ObjChar.kt

@@ -1,19 +0,0 @@
-package net.sergeych.lyng
-
-class ObjChar(val value: Char): Obj() {
-
-    override val objClass: ObjClass = type
-
-    override suspend fun compareTo(context: Context, other: Obj): Int =
-        (other as? ObjChar)?.let { value.compareTo(it.value) } ?: -1
-
-    override fun toString(): String = value.toString()
-
-    override fun inspect(): String = "'$value'"
-
-    companion object {
-        val type = ObjClass("Char").apply {
-            addFn("code") { ObjInt(thisAs<ObjChar>().value.code.toLong()) }
-        }
-    }
-}

library/src/commonMain/kotlin/net/sergeych/lyng/ObjClass.kt

@@ -1,151 +0,0 @@
-package net.sergeych.lyng
-
-val ObjClassType by lazy { ObjClass("Class") }
-
-open class ObjClass(
-    val className: String,
-    vararg val parents: ObjClass,
-) : Obj() {
-
-    var instanceConstructor: Statement? = null
-
-    val allParentsSet: Set<ObjClass> = parents.flatMap {
-        listOf(it) + it.allParentsSet
-    }.toSet()
-
-    override val objClass: ObjClass by lazy { ObjClassType }
-
-    // members: fields most often
-    private val members = mutableMapOf<String, ObjRecord>()
-
-    override fun toString(): String = className
-
-    override suspend fun compareTo(context: Context, other: Obj): Int = if (other === this) 0 else -1
-
-    override suspend fun callOn(context: Context): Obj {
-        val instance = ObjInstance(this)
-        instance.instanceContext = context.copy(newThisObj = instance,args = context.args)
-        if (instanceConstructor != null) {
-            instanceConstructor!!.execute(instance.instanceContext)
-        }
-        return instance
-    }
-
-    fun defaultInstance(): Obj = object : Obj() {
-        override val objClass: ObjClass = this@ObjClass
-    }
-
-    fun createField(
-        name: String,
-        initialValue: Obj,
-        isMutable: Boolean = false,
-        visibility: Visibility = Visibility.Public,
-        pos: Pos = Pos.builtIn
-    ) {
-        if (name in members || allParentsSet.any { name in it.members })
-            throw ScriptError(pos, "$name is already defined in $objClass or one of its supertypes")
-        members[name] = ObjRecord(initialValue, isMutable, visibility)
-    }
-
-    fun addFn(name: String, isOpen: Boolean = false, code: suspend Context.() -> Obj) {
-        createField(name, statement { code() }, isOpen)
-    }
-
-    fun addConst(name: String, value: Obj) = createField(name, value, isMutable = false)
-
-
-    /**
-     * Get instance member traversing the hierarchy if needed. Its meaning is different for different objects.
-     */
-    fun getInstanceMemberOrNull(name: String): ObjRecord? {
-        members[name]?.let { return it }
-        allParentsSet.forEach { parent -> parent.getInstanceMemberOrNull(name)?.let { return it } }
-        return null
-    }
-
-    fun getInstanceMember(atPos: Pos, name: String): ObjRecord =
-        getInstanceMemberOrNull(name)
-            ?: throw ScriptError(atPos, "symbol doesn't exist: $name")
-}
-
-/**
- * Abstract class that must provide `iterator` method that returns [ObjIterator] instance.
- */
-val ObjIterable by lazy {
-    ObjClass("Iterable").apply {
-
-        addFn("toList") {
-            val result = mutableListOf<Obj>()
-            val iterator = thisObj.invokeInstanceMethod(this, "iterator")
-
-            while (iterator.invokeInstanceMethod(this, "hasNext").toBool())
-                result += iterator.invokeInstanceMethod(this, "next")
-
-
-//        val next = iterator.getMemberOrNull("next")!!
-//        val hasNext = iterator.getMemberOrNull("hasNext")!!
-//        while( hasNext.invoke(this, iterator).toBool() )
-//            result += next.invoke(this, iterator)
-            ObjList(result)
-        }
-
-    }
-}
-
-/**
- * Collection is an iterator with `size`]
- */
-val ObjCollection by lazy {
-    val i: ObjClass = ObjIterable
-    ObjClass("Collection", i)
-}
-
-val ObjIterator by lazy { ObjClass("Iterator") }
-
-class ObjArrayIterator(val array: Obj) : Obj() {
-
-    override val objClass: ObjClass by lazy { type }
-
-    private var nextIndex = 0
-    private var lastIndex = 0
-
-    suspend fun init(context: Context) {
-        nextIndex = 0
-        lastIndex = array.invokeInstanceMethod(context, "size").toInt()
-        ObjVoid
-    }
-
-    companion object {
-        val type by lazy {
-            ObjClass("ArrayIterator", ObjIterator).apply {
-                addFn("next") {
-                    val self = thisAs<ObjArrayIterator>()
-                    if (self.nextIndex < self.lastIndex) {
-                        self.array.invokeInstanceMethod(this, "getAt", (self.nextIndex++).toObj())
-                    } else raiseError(ObjIterationFinishedException(this))
-                }
-                addFn("hasNext") {
-                    val self = thisAs<ObjArrayIterator>()
-                    if (self.nextIndex < self.lastIndex) ObjTrue else ObjFalse
-                }
-            }
-        }
-    }
-}
-
-
-val ObjArray by lazy {
-
-    /**
-     * Array abstract class is a [ObjCollection] with `getAt` method.
-     */
-    ObjClass("Array", ObjCollection).apply {
-        // we can create iterators using size/getat:
-
-        addFn("iterator") {
-            ObjArrayIterator(thisObj).also { it.init(this) }
-        }
-        addFn("isample") { "ok".toObj() }
-    }
-}
-

library/src/commonMain/kotlin/net/sergeych/lyng/ObjInstance.kt

@@ -1,55 +0,0 @@
-package net.sergeych.lyng
-
-class ObjInstance(override val objClass: ObjClass) : Obj() {
-
-    internal lateinit var instanceContext: Context
-
-    override suspend fun readField(context: Context, name: String): ObjRecord {
-        return instanceContext[name]?.let {
-            if (it.visibility.isPublic)
-                it
-            else
-                context.raiseError(ObjAccessException(context, "can't access non-public field $name"))
-        }
-            ?: super.readField(context, name)
-    }
-
-    override suspend fun writeField(context: Context, name: String, newValue: Obj) {
-        instanceContext[name]?.let { f ->
-            if (!f.visibility.isPublic)
-                ObjIllegalAssignmentException(context, "can't assign to non-public field $name")
-            if (!f.isMutable) ObjIllegalAssignmentException(context, "can't reassign val $name").raise()
-            if (f.value.assign(context, newValue) == null)
-                f.value = newValue
-        } ?: super.writeField(context, name, newValue)
-    }
-
-    override suspend fun invokeInstanceMethod(context: Context, name: String, args: Arguments): Obj =
-        instanceContext[name]?.let {
-            if (it.visibility.isPublic)
-                it.value.invoke(context, this, args)
-            else
-                context.raiseError(ObjAccessException(context, "can't invoke non-public method $name"))
-        }
-            ?: super.invokeInstanceMethod(context, name, args)
-
-    private val publicFields: Map<String, ObjRecord>
-        get() = instanceContext.objects.filter { it.value.visibility.isPublic }
-
-    override fun toString(): String {
-        val fields = publicFields.map { "${it.key}=${it.value.value}" }.joinToString(",")
-        return "${objClass.className}($fields)"
-    }
-
-    override suspend fun compareTo(context: Context, other: Obj): Int {
-        if (other !is ObjInstance) return -1
-        if (other.objClass != objClass) return -1
-        for (f in publicFields) {
-            val a = f.value.value
-            val b = other.instanceContext[f.key]!!.value
-            val d = a.compareTo(context, b)
-            if (d != 0) return d
-        }
-        return 0
-    }
-}

library/src/commonMain/kotlin/net/sergeych/lyng/ObjInt.kt

@@ -1,80 +0,0 @@
-package net.sergeych.lyng
-
-data class ObjInt(var value: Long) : Obj(), Numeric {
-    override val asStr get() = ObjString(value.toString())
-    override val longValue get() = value
-    override val doubleValue get() = value.toDouble()
-    override val toObjInt get() = this
-    override val toObjReal = ObjReal(doubleValue)
-
-    override fun byValueCopy(): Obj = ObjInt(value)
-
-    override suspend fun getAndIncrement(context: Context): Obj {
-        return ObjInt(value).also { value++ }
-    }
-
-    override suspend fun getAndDecrement(context: Context): Obj {
-        return ObjInt(value).also { value-- }
-    }
-
-    override suspend fun incrementAndGet(context: Context): Obj {
-        return ObjInt(++value)
-    }
-
-    override suspend fun decrementAndGet(context: Context): Obj {
-        return ObjInt(--value)
-    }
-
-    override suspend fun compareTo(context: Context, other: Obj): Int {
-        if (other !is Numeric) return -2
-        return value.compareTo(other.doubleValue)
-    }
-
-    override fun toString(): String = value.toString()
-
-    override val objClass: ObjClass = type
-
-    override suspend fun plus(context: Context, other: Obj): Obj =
-        if (other is ObjInt)
-            ObjInt(this.value + other.value)
-        else
-            ObjReal(this.doubleValue + other.toDouble())
-
-    override suspend fun minus(context: Context, other: Obj): Obj =
-        if (other is ObjInt)
-            ObjInt(this.value - other.value)
-        else
-            ObjReal(this.doubleValue - other.toDouble())
-
-    override suspend fun mul(context: Context, other: Obj): Obj =
-        if (other is ObjInt) {
-            ObjInt(this.value * other.value)
-        } else ObjReal(this.value * other.toDouble())
-
-    override suspend fun div(context: Context, other: Obj): Obj =
-        if (other is ObjInt)
-            ObjInt(this.value / other.value)
-        else ObjReal(this.value / other.toDouble())
-
-    override suspend fun mod(context: Context, other: Obj): Obj =
-        if (other is ObjInt)
-            ObjInt(this.value % other.value)
-        else ObjReal(this.value.toDouble() % other.toDouble())
-
-    /**
-     * We are by-value type ([byValueCopy] is implemented) so we can do in-place
-     * assignment
-     */
-    override suspend fun assign(context: Context, other: Obj): Obj? {
-        return if (other is ObjInt) {
-            value = other.value
-            this
-        } else null
-    }
-
-    companion object {
-        val type = ObjClass("Int")
-    }
-}
-
-fun Int.toObj() = ObjInt(this.toLong())

library/src/commonMain/kotlin/net/sergeych/lyng/ObjList.kt

@@ -1,137 +0,0 @@
-package net.sergeych.lyng
-
-class ObjList(val list: MutableList<Obj> = mutableListOf()) : Obj() {
-
-    init {
-        for (p in objClass.parents)
-            parentInstances.add(p.defaultInstance())
-    }
-
-    override fun toString(): String = "[${
-        list.joinToString(separator = ", ") { it.inspect() }
-    }]"
-
-    fun normalize(context: Context, index: Int, allowisEndInclusive: Boolean = false): Int {
-        val i = if (index < 0) list.size + index else index
-        if (allowisEndInclusive && i == list.size) return i
-        if (i !in list.indices) context.raiseError("index $index out of bounds for size ${list.size}")
-        return i
-    }
-
-    override suspend fun getAt(context: Context, index: Int): Obj {
-        val i = normalize(context, index)
-        return list[i]
-    }
-
-    override suspend fun putAt(context: Context, index: Int, newValue: Obj) {
-        val i = normalize(context, index)
-        list[i] = newValue
-    }
-
-    override suspend fun compareTo(context: Context, other: Obj): Int {
-        if (other !is ObjList) return -2
-        val mySize = list.size
-        val otherSize = other.list.size
-        val commonSize = minOf(mySize, otherSize)
-        for (i in 0..<commonSize) {
-            if (list[i].compareTo(context, other.list[i]) != 0) {
-                return list[i].compareTo(context, other.list[i])
-            }
-        }
-        // equal so far, longer is greater:
-        return when {
-            mySize < otherSize -> -1
-            mySize > otherSize -> 1
-            else -> 0
-        }
-    }
-
-    override suspend fun plus(context: Context, other: Obj): Obj =
-        when {
-            other is ObjList ->
-                ObjList((list + other.list).toMutableList())
-
-            other.isInstanceOf(ObjIterable) -> {
-                val l = other.callMethod<ObjList>(context, "toList")
-                ObjList((list + l.list).toMutableList())
-            }
-
-            else ->
-                context.raiseError("'+': can't concatenate $this with $other")
-        }
-
-
-    override suspend fun plusAssign(context: Context, other: Obj): Obj {
-        // optimization
-        if (other is ObjList) {
-            list += other.list
-            return this
-        }
-        if (other.isInstanceOf(ObjIterable)) {
-            val otherList = other.invokeInstanceMethod(context, "toList") as ObjList
-            list += otherList.list
-        } else
-            list += other
-        return this
-    }
-
-    override val objClass: ObjClass
-        get() = type
-
-    companion object {
-        val type = ObjClass("List", ObjArray).apply {
-
-            createField("size",
-                statement {
-                    (thisObj as ObjList).list.size.toObj()
-                }
-            )
-            addFn("getAt") {
-                requireExactCount(1)
-                thisAs<ObjList>().getAt(this, requiredArg<ObjInt>(0).value.toInt())
-            }
-            addFn("putAt") {
-                requireExactCount(2)
-                val newValue = args[1]
-                thisAs<ObjList>().putAt(this, requiredArg<ObjInt>(0).value.toInt(), newValue)
-                newValue
-            }
-            createField("add",
-                statement {
-                    val l = thisAs<ObjList>().list
-                    for (a in args) l.add(a)
-                    ObjVoid
-                }
-            )
-            createField("addAt",
-                statement {
-                    if (args.size < 2) raiseError("addAt takes 2+ arguments")
-                    val l = thisAs<ObjList>()
-                    var index = l.normalize(
-                        this, requiredArg<ObjInt>(0).value.toInt(),
-                        allowisEndInclusive = true
-                    )
-                    for (i in 1..<args.size) l.list.add(index++, args[i])
-                    ObjVoid
-                }
-            )
-            addFn("removeAt") {
-                val self = thisAs<ObjList>()
-                val start = self.normalize(this, requiredArg<ObjInt>(0).value.toInt())
-                if (args.size == 2) {
-                    val end = requireOnlyArg<ObjInt>().value.toInt()
-                    self.list.subList(start, self.normalize(this, end)).clear()
-                } else
-                    self.list.removeAt(start)
-                self
-            }
-            addFn("removeRangeInclusive") {
-                val self = thisAs<ObjList>()
-                val start = self.normalize(this, requiredArg<ObjInt>(0).value.toInt())
-                val end = self.normalize(this, requiredArg<ObjInt>(1).value.toInt()) + 1
-                self.list.subList(start, end).clear()
-                self
-            }
-        }
-    }
-}

library/src/commonMain/kotlin/net/sergeych/lyng/ObjRange.kt

@@ -1,101 +0,0 @@
-package net.sergeych.lyng
-
-class ObjRange(val start: Obj?, val end: Obj?, val isEndInclusive: Boolean) : Obj() {
-
-    override val objClass: ObjClass = type
-
-    override fun toString(): String {
-        val result = StringBuilder()
-        result.append("${start?.inspect() ?: '∞'} ..")
-        if (!isEndInclusive) result.append('<')
-        result.append(" ${end?.inspect() ?: '∞'}")
-        return result.toString()
-    }
-
-    suspend fun containsRange(context: Context, other: ObjRange): Boolean {
-        if (start != null) {
-            // our start is not -∞ so other start should be GTE or is not contained:
-            if (other.start != null && start.compareTo(context, other.start) > 0) return false
-        }
-        if (end != null) {
-            // same with the end: if it is open, it can't be contained in ours:
-            if (other.end == null) return false
-            // both exists, now there could be 4 cases:
-            return when {
-                other.isEndInclusive && isEndInclusive ->
-                    end.compareTo(context, other.end) >= 0
-
-                !other.isEndInclusive && !isEndInclusive ->
-                    end.compareTo(context, other.end) >= 0
-
-                other.isEndInclusive && !isEndInclusive ->
-                    end.compareTo(context, other.end) > 0
-
-                !other.isEndInclusive && isEndInclusive ->
-                    end.compareTo(context, other.end) >= 0
-
-                else -> throw IllegalStateException("unknown comparison")
-            }
-        }
-        return true
-    }
-
-    override suspend fun contains(context: Context, other: Obj): Boolean {
-
-        if (other is ObjRange)
-            return containsRange(context, other)
-
-        if (start == null && end == null) return true
-        if (start != null) {
-            if (start.compareTo(context, other) > 0) return false
-        }
-        if (end != null) {
-            val cmp = end.compareTo(context, other)
-            if (isEndInclusive && cmp < 0 || !isEndInclusive && cmp <= 0) return false
-        }
-        return true
-    }
-
-    val isIntRange: Boolean by lazy {
-        start is ObjInt && end is ObjInt
-    }
-
-    val isCharRange: Boolean by lazy {
-        start is ObjChar && end is ObjChar
-    }
-
-    override suspend fun compareTo(context: Context, other: Obj): Int {
-        return (other as? ObjRange)?.let {
-            if( start == other.start && end == other.end ) 0 else -1
-        }
-            ?: -1
-    }
-
-    companion object {
-        val type = ObjClass("Range", ObjIterable).apply {
-            addFn("start") {
-                thisAs<ObjRange>().start ?: ObjNull
-            }
-            addFn("end") {
-                thisAs<ObjRange>().end ?: ObjNull
-            }
-            addFn("isOpen") {
-                thisAs<ObjRange>().let { it.start == null || it.end == null }.toObj()
-            }
-            addFn("isIntRange") {
-                thisAs<ObjRange>().isIntRange.toObj()
-            }
-            addFn("isCharRange") {
-                thisAs<ObjRange>().isCharRange.toObj()
-            }
-            addFn("isEndInclusive") {
-                thisAs<ObjRange>().isEndInclusive.toObj()
-            }
-            addFn("iterator") {
-                val self = thisAs<ObjRange>()
-                ObjRangeIterator(self).apply { init() }
-            }
-        }
-    }
-}
-

library/src/commonMain/kotlin/net/sergeych/lyng/ObjRangeIterator.kt

@@ -1,49 +0,0 @@
-package net.sergeych.lyng
-
-class ObjRangeIterator(val self: ObjRange) : Obj() {
-
-    private var nextIndex = 0
-    private var lastIndex = 0
-    private var isCharRange: Boolean = false
-
-    override val objClass: ObjClass = type
-
-    fun Context.init() {
-        if (self.start == null || self.end == null)
-            raiseError("next is only available for finite ranges")
-        isCharRange = self.isCharRange
-        lastIndex = if (self.isIntRange || self.isCharRange) {
-            if (self.isEndInclusive)
-                self.end.toInt() - self.start.toInt() + 1
-            else
-                self.end.toInt() - self.start.toInt()
-        } else {
-            raiseError("not implemented iterator for range of $this")
-        }
-    }
-
-    fun hasNext(): Boolean = nextIndex < lastIndex
-
-    fun next(context: Context): Obj =
-        if (nextIndex < lastIndex) {
-            val x = if (self.isEndInclusive)
-                self.start!!.toLong() + nextIndex++
-            else
-                self.start!!.toLong() + nextIndex++
-            if( isCharRange ) ObjChar(x.toInt().toChar()) else ObjInt(x)
-        }
-        else {
-            context.raiseError(ObjIterationFinishedException(context))
-        }
-
-    companion object {
-        val type = ObjClass("RangeIterator", ObjIterable).apply {
-            addFn("hasNext") {
-                thisAs<ObjRangeIterator>().hasNext().toObj()
-            }
-            addFn("next") {
-                thisAs<ObjRangeIterator>().next(this)
-            }
-        }
-    }
-}

library/src/commonMain/kotlin/net/sergeych/lyng/ObjReal.kt

@@ -1,49 +0,0 @@
-package net.sergeych.lyng
-
-import kotlin.math.floor
-import kotlin.math.roundToLong
-
-data class ObjReal(val value: Double) : Obj(), Numeric {
-    override val asStr by lazy { ObjString(value.toString()) }
-    override val longValue: Long by lazy { floor(value).toLong() }
-    override val doubleValue: Double by lazy { value }
-    override val toObjInt: ObjInt by lazy { ObjInt(longValue) }
-    override val toObjReal: ObjReal by lazy { ObjReal(value) }
-
-    override fun byValueCopy(): Obj = ObjReal(value)
-
-    override suspend fun compareTo(context: Context, other: Obj): Int {
-        if (other !is Numeric) return -2
-        return value.compareTo(other.doubleValue)
-    }
-
-    override fun toString(): String = value.toString()
-
-    override val objClass: ObjClass = type
-
-    override suspend fun plus(context: Context, other: Obj): Obj =
-        ObjReal(this.value + other.toDouble())
-
-    override suspend fun minus(context: Context, other: Obj): Obj =
-        ObjReal(this.value - other.toDouble())
-
-    override suspend fun mul(context: Context, other: Obj): Obj =
-        ObjReal(this.value * other.toDouble())
-
-    override suspend fun div(context: Context, other: Obj): Obj =
-        ObjReal(this.value / other.toDouble())
-
-    override suspend fun mod(context: Context, other: Obj): Obj =
-        ObjReal(this.value % other.toDouble())
-
-    companion object {
-        val type: ObjClass = ObjClass("Real").apply {
-            createField(
-                "roundToInt",
-                statement(Pos.builtIn) {
-                    (it.thisObj as ObjReal).value.roundToLong().toObj()
-                },
-            )
-        }
-    }
-}

library/src/commonMain/kotlin/net/sergeych/lyng/ObjString.kt

@@ -1,72 +0,0 @@
-package net.sergeych.lyng
-
-import kotlinx.serialization.SerialName
-import kotlinx.serialization.Serializable
-
-@Serializable
-@SerialName("string")
-data class ObjString(val value: String) : Obj() {
-
-    override suspend fun compareTo(context: Context, other: Obj): Int {
-        if (other !is ObjString) return -2
-        return this.value.compareTo(other.value)
-    }
-
-    override fun toString(): String = value
-
-    override val asStr: ObjString by lazy { this }
-
-    override fun inspect(): String {
-        return "\"$value\""
-    }
-
-    override val objClass: ObjClass
-        get() = type
-
-    override suspend fun plus(context: Context, other: Obj): Obj {
-        return ObjString(value + other.asStr.value)
-    }
-
-    override suspend fun getAt(context: Context, index: Int): Obj {
-        return ObjChar(value[index])
-    }
-
-    companion object {
-        val type = ObjClass("String").apply {
-            addConst("startsWith",
-                statement {
-                    ObjBool(thisAs<ObjString>().value.startsWith(requiredArg<ObjString>(0).value))
-                })
-            addConst("length",
-                statement { ObjInt(thisAs<ObjString>().value.length.toLong()) }
-            )
-            addFn("takeLast") {
-                thisAs<ObjString>().value.takeLast(
-                    requiredArg<ObjInt>(0).toInt()
-                ).let(::ObjString)
-            }
-            addFn("take") {
-                thisAs<ObjString>().value.take(
-                    requiredArg<ObjInt>(0).toInt()
-                ).let(::ObjString)
-            }
-            addFn("drop") {
-                thisAs<ObjString>().value.drop(
-                    requiredArg<ObjInt>(0).toInt()
-                ).let(::ObjString)
-            }
-            addFn("dropLast") {
-                thisAs<ObjString>().value.dropLast(
-                    requiredArg<ObjInt>(0).toInt()
-                ).let(::ObjString)
-            }
-            addFn("lower") {
-                thisAs<ObjString>().value.lowercase().let(::ObjString)
-            }
-            addFn("upper") {
-                thisAs<ObjString>().value.uppercase().let(::ObjString)
-            }
-            addFn("size") { ObjInt(thisAs<ObjString>().value.length.toLong()) }
-        }
-    }
-}

library/src/commonMain/kotlin/net/sergeych/lyng/Script.kt

@@ -1,171 +0,0 @@
-package net.sergeych.lyng
-
-import kotlinx.coroutines.delay
-import kotlin.math.*
-
-class Script(
-    override val pos: Pos,
-    private val statements: List<Statement> = emptyList(),
-//    private val catchReturn: Boolean = false,
-) : Statement() {
-
-    override suspend fun execute(context: Context): Obj {
-        var lastResult: Obj = ObjVoid
-        for (s in statements) {
-            lastResult = s.execute(context)
-        }
-        return lastResult
-    }
-
-    suspend fun execute() = execute(defaultContext.copy(pos = pos))
-
-    companion object {
-        val defaultContext: Context = Context().apply {
-            ObjException.addExceptionsToContext(this)
-            addFn("println") {
-                for ((i, a) in args.withIndex()) {
-                    if (i > 0) print(' ' + a.asStr.value)
-                    else print(a.asStr.value)
-                }
-                println()
-                ObjVoid
-            }
-            addFn("floor") {
-                val x = args.firstAndOnly()
-                (if (x is ObjInt) x
-                else ObjReal(floor(x.toDouble())))
-            }
-            addFn("ceil") {
-                val x = args.firstAndOnly()
-                (if (x is ObjInt) x
-                else ObjReal(ceil(x.toDouble())))
-            }
-            addFn("round") {
-                val x = args.firstAndOnly()
-                (if (x is ObjInt) x
-                else ObjReal(round(x.toDouble())))
-            }
-
-            addFn("sin") {
-                ObjReal(sin(args.firstAndOnly().toDouble()))
-            }
-            addFn("cos") {
-                ObjReal(cos(args.firstAndOnly().toDouble()))
-            }
-            addFn("tan") {
-                ObjReal(tan(args.firstAndOnly().toDouble()))
-            }
-            addFn("asin") {
-                ObjReal(asin(args.firstAndOnly().toDouble()))
-            }
-            addFn("acos") {
-                ObjReal(acos(args.firstAndOnly().toDouble()))
-            }
-            addFn("atan") {
-                ObjReal(atan(args.firstAndOnly().toDouble()))
-            }
-
-            addFn("sinh") {
-                ObjReal(sinh(args.firstAndOnly().toDouble()))
-            }
-            addFn("cosh") {
-                ObjReal(cosh(args.firstAndOnly().toDouble()))
-            }
-            addFn("tanh") {
-                ObjReal(tanh(args.firstAndOnly().toDouble()))
-            }
-            addFn("asinh") {
-                ObjReal(asinh(args.firstAndOnly().toDouble()))
-            }
-            addFn("acosh") {
-                ObjReal(acosh(args.firstAndOnly().toDouble()))
-            }
-            addFn("atanh") {
-                ObjReal(atanh(args.firstAndOnly().toDouble()))
-            }
-
-            addFn("exp") {
-                ObjReal(exp(args.firstAndOnly().toDouble()))
-            }
-            addFn("ln") {
-                ObjReal(ln(args.firstAndOnly().toDouble()))
-            }
-
-            addFn("log10") {
-                ObjReal(log10(args.firstAndOnly().toDouble()))
-            }
-
-            addFn("log2") {
-                ObjReal(log2(args.firstAndOnly().toDouble()))
-            }
-
-            addFn("pow") {
-                requireExactCount(2)
-                ObjReal(
-                    (args[0].toDouble()).pow(args[1].toDouble())
-                )
-            }
-            addFn("sqrt") {
-                ObjReal(
-                    sqrt(args.firstAndOnly().toDouble())
-                )
-            }
-            addFn( "abs" ) {
-                val x = args.firstAndOnly()
-                if( x is ObjInt ) ObjInt( x.value.absoluteValue ) else ObjReal( x.toDouble().absoluteValue )
-            }
-
-            addVoidFn("assert") {
-                val cond = requiredArg<ObjBool>(0)
-                if( !cond.value == true )
-                    raiseError(ObjAssertionFailedException(this,"Assertion failed"))
-            }
-
-            addVoidFn("assertEquals") {
-                val a = requiredArg<Obj>(0)
-                val b = requiredArg<Obj>(1)
-                if( a.compareTo(this, b) != 0 )
-                    raiseError(ObjAssertionFailedException(this,"Assertion failed: ${a.inspect()} == ${b.inspect()}"))
-            }
-            addFn("assertThrows") {
-                val code = requireOnlyArg<Statement>()
-                val result =try {
-                    code.execute(this)
-                    null
-                }
-                catch( e: ExecutionError ) {
-                    e.errorObject
-                }
-                catch (e: ScriptError) {
-                    ObjNull
-                }
-                result ?: raiseError(ObjAssertionFailedException(this,"Expected exception but nothing was thrown"))
-            }
-
-            addVoidFn("delay") {
-                delay((this.args.firstAndOnly().toDouble()/1000.0).roundToLong())
-            }
-
-            addConst("Real", ObjReal.type)
-            addConst("String", ObjString.type)
-            addConst("Int", ObjInt.type)
-            addConst("Bool", ObjBool.type)
-            addConst("Char", ObjChar.type)
-            addConst("List", ObjList.type)
-            addConst("Range", ObjRange.type)
-            @Suppress("RemoveRedundantQualifierName")
-            addConst("Callable", Statement.type)
-            // interfaces
-            addConst("Iterable", ObjIterable)
-            addConst("Array", ObjArray)
-            addConst("Class", ObjClassType)
-            addConst("Object", Obj().objClass)
-
-            val pi = ObjReal(PI)
-            addConst("π", pi)
-            getOrCreateNamespace("Math").apply {
-                addConst("PI", pi)
-            }
-        }
-    }
-}

library/src/commonMain/kotlin/net/sergeych/lyng/ScriptError.kt

@@ -1,15 +0,0 @@
-@file:Suppress("CanBeParameter")
-
-package net.sergeych.lyng
-
-open class ScriptError(val pos: Pos, val errorMessage: String,cause: Throwable?=null) : Exception(
-    """
-        $pos: Error: $errorMessage
-        
-        ${pos.currentLine}
-        ${"-".repeat(pos.column)}^
-    """.trimIndent(),
-    cause
-)
-
-class ExecutionError(val errorObject: ObjException) : ScriptError(errorObject.context.pos, errorObject.message)

library/src/commonMain/kotlin/net/sergeych/lyng/Source.kt

@@ -1,15 +0,0 @@
-package net.sergeych.lyng
-
-class Source(val fileName: String, text: String) {
-
-    val lines = text.lines().map { it.trimEnd() }
-
-    companion object {
-        val builtIn: Source by lazy { Source("built-in", "") }
-        val UNKNOWN: Source by lazy { Source("UNKNOWN", "") }
-    }
-
-    val startPos: Pos = Pos(this, 0, 0)
-
-    fun posAt(line: Int, column: Int): Pos = Pos(this, line, column)
-}

library/src/commonMain/kotlin/net/sergeych/lyng/SymbolSpace.kt

@@ -1,13 +0,0 @@
-package net.sergeych.lyng
-
-
-
-class Symbols(
-    unitType: UnitType,
-    val name: String,
-    val x: TypeDecl
-) {
-    enum class UnitType {
-        Module, Function, Lambda
-    }
-}

library/src/commonMain/kotlin/net/sergeych/lyng/Token.kt

@@ -1,30 +0,0 @@
-package net.sergeych.lyng
-
-data class Token(val value: String, val pos: Pos, val type: Type) {
-    val isComment: Boolean by lazy { type == Type.SINLGE_LINE_COMMENT || type == Type.MULTILINE_COMMENT }
-
-    @Suppress("unused")
-    enum class Type {
-        ID, INT, REAL, HEX, STRING, CHAR,
-        LPAREN, RPAREN, LBRACE, RBRACE, LBRACKET, RBRACKET, COMMA,
-        SEMICOLON, COLON,
-        PLUS, MINUS, STAR, SLASH, PERCENT,
-        ASSIGN, PLUSASSIGN, MINUSASSIGN, STARASSIGN, SLASHASSIGN, PERCENTASSIGN,
-        PLUS2, MINUS2,
-        IN, NOTIN, IS, NOTIS,
-        EQ, NEQ, LT, LTE, GT, GTE, REF_EQ, REF_NEQ,
-        SHUTTLE,
-        AND, BITAND, OR, BITOR, NOT, BITNOT, DOT, ARROW, QUESTION, COLONCOLON,
-        SINLGE_LINE_COMMENT, MULTILINE_COMMENT,
-        LABEL, ATLABEL, // label@ at@label
-        PRIVATE, PROTECTED,
-        //PUBLIC, PROTECTED, INTERNAL, EXPORT, OPEN, INLINE, OVERRIDE, ABSTRACT, SEALED, EXTERNAL, VAL, VAR, CONST, TYPE, FUN, CLASS, INTERFACE, ENUM, OBJECT, TRAIT, THIS,
-        ELLIPSIS, DOTDOT, DOTDOTLT,
-        NEWLINE,
-        EOF,
-    }
-
-    companion object {
-//        fun eof(parser: Parser) = Token("", parser.currentPos, Type.EOF)
-    }
-}

library/src/commonMain/kotlin/net/sergeych/lyng/TypeDecl.kt

@@ -1,21 +0,0 @@
-package net.sergeych.lyng
-
-sealed class TypeDecl {
-    // ??
-    data class Fn(val argTypes: List<ArgsDeclaration.Item>, val retType: TypeDecl) : TypeDecl()
-    object Obj : TypeDecl()
-}
-
-/*
-To use in the compiler, we need symbol information when:
-
-- declaring a class: the only way to export its public/protected symbols is to know it in compiler time
-- importing a module: actually,  we cam try to do it in a more efficient way.
-
-Importing module:
-
-The moudule is efficiently a statement, that initializes it with all its symbols modifying some context.
-
-The thing is, we need only
-
- */

library/src/commonMain/kotlin/net/sergeych/lyng/Visibility.kt

@@ -1,8 +0,0 @@
-package net.sergeych.lyng
-
-enum class Visibility {
-    Public, Private, Protected;//, Internal
-    val isPublic by lazy { this == Public }
-    @Suppress("unused")
-    val isProtected by lazy { this == Protected }
-}

library/src/commonMain/kotlin/net/sergeych/lyng/globals.kt

@@ -1,4 +0,0 @@
-package net.sergeych.lyng
-
-
-val LyngVersion = BuildKonfig.version

library/src/commonMain/kotlin/net/sergeych/lyng/statements.kt

@@ -1,60 +0,0 @@
-package net.sergeych.lyng
-
-fun String.toSource(name: String = "eval"): Source = Source(name, this)
-
-sealed class ObjType {
-    object Any : ObjType()
-    object Int : ObjType()
-}
-
-
-@Suppress("unused")
-abstract class Statement(
-    val isStaticConst: Boolean = false,
-    val isConst: Boolean = false,
-    val returnType: ObjType = ObjType.Any
-) : Obj() {
-
-    override val objClass: ObjClass = type
-
-    abstract val pos: Pos
-    abstract suspend fun execute(context: Context): Obj
-
-    override suspend fun compareTo(context: Context,other: Obj): Int {
-        throw UnsupportedOperationException("not comparable")
-    }
-
-    override suspend fun callOn(context: Context): Obj {
-        return execute(context)
-    }
-
-    override fun toString(): String = "Callable@${this.hashCode()}"
-
-    companion object {
-        val type = ObjClass("Callable")
-    }
-
-}
-
-fun Statement.raise(text: String): Nothing {
-    throw ScriptError(pos, text)
-}
-
-@Suppress("unused")
-fun Statement.require(cond: Boolean, message: () -> String) {
-    if (!cond) raise(message())
-}
-
-fun statement(pos: Pos, isStaticConst: Boolean = false, isConst: Boolean = false, f: suspend (Context) -> Obj): Statement =
-    object : Statement(isStaticConst, isConst) {
-        override val pos: Pos = pos
-        override suspend fun execute(context: Context): Obj = f(context)
-    }
-
-fun statement(isStaticConst: Boolean = false, isConst: Boolean = false, f: suspend Context.() -> Obj): Statement =
-    object : Statement(isStaticConst, isConst) {
-        override val pos: Pos = Pos.builtIn
-        override suspend fun execute(context: Context): Obj = f(context)
-    }
-
-

lyng/build.gradle.kts

@@ -1,5 +1,22 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
 plugins {
-    kotlin("multiplatform") version "2.1.21"
+    alias(libs.plugins.kotlinMultiplatform)
 }
 
 group = "net.sergeych"
@@ -14,6 +31,15 @@ repositories {
 }
 
 kotlin {
+    // Suppress Beta warning for expect/actual classes across all targets in this module
+    targets.configureEach {
+        compilations.configureEach {
+            compilerOptions.configure {
+                freeCompilerArgs.add("-Xexpect-actual-classes")
+            }
+        }
+    }
+
     jvm {
         binaries {
             executable {
@@ -29,11 +55,11 @@ kotlin {
     sourceSets {
         val commonMain by getting {
             dependencies {
-                implementation(project(":library"))
+                implementation(kotlin("stdlib-common"))
+                implementation(project(":lynglib"))
                 implementation(libs.okio)
-
                 implementation(libs.clikt)
-
+                implementation(kotlin("stdlib-common"))
                 // optional support for rendering markdown in help messages
 //                implementation(libs.clikt.markdown)
             }
@@ -42,9 +68,15 @@ kotlin {
             dependencies {
                 implementation(kotlin("test-common"))
                 implementation(kotlin("test-annotations-common"))
+                implementation(libs.kotlinx.coroutines.core)
                 implementation(libs.okio.fakefilesystem)
             }
         }
+//        val nativeMain by getting {
+//            dependencies {
+//                implementation(kotlin("stdlib-common"))
+//            }
+//        }
         val linuxX64Main by getting {
 
         }

lyng/src/commonMain/kotlin/Common.kt

@@ -1,12 +1,37 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
 package net.sergeych
 
 import com.github.ajalt.clikt.core.CliktCommand
+import com.github.ajalt.clikt.core.Context
+import com.github.ajalt.clikt.core.main
 import com.github.ajalt.clikt.parameters.arguments.argument
 import com.github.ajalt.clikt.parameters.arguments.multiple
 import com.github.ajalt.clikt.parameters.arguments.optional
 import com.github.ajalt.clikt.parameters.options.flag
 import com.github.ajalt.clikt.parameters.options.option
-import net.sergeych.lyng.*
+import kotlinx.coroutines.runBlocking
+import net.sergeych.lyng.LyngVersion
+import net.sergeych.lyng.Script
+import net.sergeych.lyng.ScriptError
+import net.sergeych.lyng.Source
+import net.sergeych.lyng.obj.*
+import net.sergeych.mp_tools.globalDefer
 import okio.FileSystem
 import okio.Path.Companion.toPath
 import okio.SYSTEM
@@ -17,18 +42,51 @@ import okio.use
 
 expect fun exit(code: Int)
 
-val baseContext = Context().apply {
+expect class ShellCommandExecutor {
+    fun executeCommand(command: String): CommandResult
+
+    companion object {
+        fun create(): ShellCommandExecutor
+    }
+}
+
+data class CommandResult(
+    val exitCode: Int,
+    val output: String,
+    val error: String
+)
+
+val baseScopeDefer = globalDefer {
+    Script.newScope().apply {
         addFn("exit") {
             exit(requireOnlyArg<ObjInt>().toInt())
             ObjVoid
         }
     }
+}
 
-class Lyng(val launcher: (suspend () -> Unit) -> Unit) : CliktCommand() {
+fun runMain(args: Array<String>) {
+    if(args.isNotEmpty()) {
+        if( args.size >= 2 && args[0] == "--" ) {
+            // -- -file.lyng <args>
+            executeFileWithArgs(args[1], args.drop(2))
+            return
+        } else if( args[0][0] != '-') {
+            // file.lyng <args>
+            executeFileWithArgs(args[0], args.drop(1))
+            return
+        }
+    }
+    // normal processing
+    Lyng { runBlocking { it() } }.main(args)
+}
+
+private class Lyng(val launcher: (suspend () -> Unit) -> Unit) : CliktCommand() {
 
     override val printHelpOnEmptyArgs = true
 
     val version by option("-v", "--version", help = "Print version and exit").flag()
+    val benchmark by option("--benchmark", help = "Run JVM microbenchmarks and exit").flag()
     val script by argument(help = "one or more scripts to execute").optional()
     val execute: String? by option(
         "-x", "--execute", help = """
@@ -38,7 +96,7 @@ class Lyng(val launcher: (suspend () -> Unit) -> Unit) : CliktCommand() {
 
     val args by argument(help = "arguments for script").multiple()
 
-    override fun help(context: com.github.ajalt.clikt.core.Context): String =
+    override fun help(context: Context): String =
         """
             The Lyng script language interpreter, language version is $LyngVersion.
             
@@ -48,6 +106,8 @@ class Lyng(val launcher: (suspend () -> Unit) -> Unit) : CliktCommand() {
         """.trimIndent()
 
     override fun run() {
+        runBlocking {
+            val baseScope = baseScopeDefer.await()
             when {
                 version -> {
                     println("Lyng language version ${LyngVersion}")
@@ -57,7 +117,7 @@ class Lyng(val launcher: (suspend () -> Unit) -> Unit) : CliktCommand() {
                     val objargs = mutableListOf<String>()
                     script?.let { objargs += it }
                     objargs += args
-                baseContext.addConst(
+                    baseScope.addConst(
                         "ARGV", ObjList(
                             objargs.map { ObjString(it) }.toMutableList()
                         )
@@ -65,7 +125,7 @@ class Lyng(val launcher: (suspend () -> Unit) -> Unit) : CliktCommand() {
                     launcher {
                         // there is no script name, it is a first argument instead:
                         processErrors {
-                        baseContext.eval(execute!!)
+                            baseScope.eval(execute!!)
                         }
                     }
                 }
@@ -81,22 +141,35 @@ class Lyng(val launcher: (suspend () -> Unit) -> Unit) : CliktCommand() {
                         )
                         echoFormattedHelp()
                     } else {
-                    baseContext.addConst("ARGV", ObjList(args.map { ObjString(it) }.toMutableList()))
+                        baseScope.addConst("ARGV", ObjList(args.map { ObjString(it) }.toMutableList()))
                         launcher { executeFile(script!!) }
                     }
                 }
             }
         }
     }
+}
+
+fun executeFileWithArgs(fileName: String, args: List<String>) {
+    runBlocking {
+        baseScopeDefer.await().addConst("ARGV", ObjList(args.map { ObjString(it) }.toMutableList()))
+        executeFile(fileName)
+    }
+}
 
 suspend fun executeFile(fileName: String) {
-    val text = FileSystem.SYSTEM.source(fileName.toPath()).use { fileSource ->
+    var text = FileSystem.SYSTEM.source(fileName.toPath()).use { fileSource ->
         fileSource.buffer().use { bs ->
             bs.readUtf8()
         }
     }
+    if( text.startsWith("#!") ) {
+        // skip shebang
+        val pos = text.indexOf('\n')
+        text = text.substring(pos + 1)
+    }
     processErrors {
-        Compiler().compile(Source(fileName, text)).execute(baseContext)
+        baseScopeDefer.await().eval(Source(fileName, text))
     }
 }
 

lyng/src/jvmMain/kotlin/Common.jvm.kt

@@ -1,3 +1,20 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
 package net.sergeych
 
 import kotlin.system.exitProcess

lyng/src/jvmMain/kotlin/Shell.jvm.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+@file:Suppress("EXPECT_ACTUAL_CLASSIFIERS_ARE_IN_BETA_WARNING")
+
+package net.sergeych
+
+// Alternative implementation for native targets
+actual class ShellCommandExecutor() {
+    actual fun executeCommand(command: String): CommandResult {
+        val process = ProcessBuilder("/bin/sh", "-c", command).start()
+        val exitCode = process.waitFor()
+        val output = process.inputStream.bufferedReader().readText()
+        val error = process.errorStream.bufferedReader().readText()
+
+        return CommandResult(
+            exitCode = exitCode,
+            output = output.trim(),
+            error = error.trim()
+        )
+    }
+
+    actual companion object {
+        actual fun create(): ShellCommandExecutor = ShellCommandExecutor()
+    }
+}

lyng/src/jvmMain/kotlin/net/sergeych/lyng_cli/Benchmark.kt

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package net.sergeych.lyng_cli
+
+import kotlinx.coroutines.runBlocking
+import net.sergeych.lyng.Compiler
+import net.sergeych.lyng.Script
+
+object BenchmarkRunner {
+    private fun format(nanos: Long, iters: Int): String {
+        val secs = nanos / 1_000_000_000.0
+        val ips = iters / secs
+        return "%.3f s, %.0f ops/s".format(secs, ips)
+    }
+
+    private suspend fun runCase(name: String, code: String, iters: Int): Pair<String, String> {
+        val script = Compiler.compile(code)
+        // warmup
+        repeat(2) { script.execute(Script.newScope()) }
+        val start = System.nanoTime()
+        repeat(iters) { script.execute(Script.newScope()) }
+        val end = System.nanoTime()
+        return name to format(end - start, iters)
+    }
+
+    fun runAll() = runBlocking {
+        val iterations = 2000
+        val cases = listOf(
+            // Field get/set in a loop
+            "field_inc" to """
+                class C { var x = 0 }
+                var c = C()
+                var i = 0
+                while( i < 1000 ) { c.x = c.x + 1; i = i + 1 }
+                c.x
+            """.trimIndent(),
+            // Pure arithmetic with literals
+            "arith_literals" to """
+                var s = 0
+                var i = 0
+                while( i < 1000 ) { s = s + 1 + 2 + 3 + 4 + 5; i = i + 1 }
+                s
+            """.trimIndent(),
+            // Method call overhead via instance method
+            "method_call" to """
+                class C { fun inc() { this.x = this.x + 1 } var x = 0 }
+                var c = C()
+                var i = 0
+                while( i < 1000 ) { c.inc(); i = i + 1 }
+                c.x
+            """.trimIndent()
+        )
+
+        println("[BENCHMARK] iterations per case: $iterations")
+        for ((name, code) in cases) {
+            val (n, res) = runCase(name, code, iterations)
+            println("[BENCHMARK] $n: $res")
+        }
+    }
+}

lyng/src/jvmMain/kotlin/net/sergeych/lyng_cli/Main.kt

@@ -1,9 +1,28 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
 package net.sergeych.lyng_cli
 
-import com.github.ajalt.clikt.core.main
+import net.sergeych.runMain
-import kotlinx.coroutines.runBlocking
-import net.sergeych.Lyng
 
 fun main(args: Array<String>) {
-    Lyng({ runBlocking { it() } }).main(args)
+    if (args.contains("--benchmark")) {
+        BenchmarkRunner.runAll()
+        return
+    }
+    runMain(args)
 }

lyng/src/linuxX64Main/kotlin/Main.kt

@@ -1,7 +1,22 @@
-import com.github.ajalt.clikt.core.main
+/*
-import kotlinx.coroutines.runBlocking
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
-import net.sergeych.Lyng
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+import net.sergeych.runMain
 
 fun main(args: Array<String>) {
-    Lyng( { runBlocking { it() } }).main(args)
+    runMain(args)
 }

lyng/src/nativeMain/kotlin/Common.native.kt

@@ -1,7 +1,67 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+@file:OptIn(ExperimentalForeignApi::class, ExperimentalForeignApi::class, ExperimentalForeignApi::class,
+    ExperimentalForeignApi::class
+)
+
 package net.sergeych
 
+import kotlinx.cinterop.*
+import platform.posix.fgets
+import platform.posix.pclose
+import platform.posix.popen
 import kotlin.system.exitProcess
 
+actual class ShellCommandExecutor() {
+    actual fun executeCommand(command: String): CommandResult {
+        val outputBuilder = StringBuilder()
+        val errorBuilder = StringBuilder()
+
+        val fp = popen(command, "r") ?: return CommandResult(
+            exitCode = -1,
+            output = "",
+            error = "Failed to execute command"
+        )
+
+        val buffer = ByteArray(4096)
+        while (true) {
+            val bytesRead = buffer.usePinned { pinned ->
+                fgets(pinned.addressOf(0), buffer.size.convert(), fp)
+            }
+            if (bytesRead == null) break
+            outputBuilder.append(bytesRead.toKString())
+        }
+
+        val status = pclose(fp)
+        val exitCode = if (status == 0) 0 else 1
+
+        return CommandResult(
+            exitCode = exitCode,
+            output = outputBuilder.toString().trim(),
+            error = errorBuilder.toString().trim()
+        )
+    }
+
+    actual companion object {
+        actual fun create(): ShellCommandExecutor = ShellCommandExecutor()
+    }
+}
+
 actual fun exit(code: Int) {
     exitProcess(code)
 }

lynglib/build.gradle.kts

@@ -0,0 +1,221 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+import com.codingfeline.buildkonfig.compiler.FieldSpec.Type.STRING
+import org.jetbrains.kotlin.gradle.ExperimentalKotlinGradlePluginApi
+import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+group = "net.sergeych"
+version = "1.0.4-SNAPSHOT"
+
+// Removed legacy buildscript classpath declarations; plugins are applied via the plugins DSL below
+
+plugins {
+    alias(libs.plugins.kotlinMultiplatform)
+    alias(libs.plugins.androidLibrary)
+//    alias(libs.plugins.vanniktech.mavenPublish)
+    kotlin("plugin.serialization") version "2.2.21"
+    id("com.codingfeline.buildkonfig") version "0.17.1"
+    `maven-publish`
+}
+
+buildkonfig {
+    packageName = "net.sergeych.lyng"
+    // objectName = "YourAwesomeConfig"
+    // exposeObjectWithName = "YourAwesomePublicConfig"
+
+    defaultConfigs {
+        buildConfigField(STRING, "bcprovider", "codingfeline")
+        buildConfigField(STRING, "version", version.toString())
+    }
+}
+
+kotlin {
+    jvm()
+    androidTarget {
+        publishLibraryVariants("release")
+        @OptIn(ExperimentalKotlinGradlePluginApi::class)
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_11)
+        }
+    }
+    iosX64()
+    iosArm64()
+    iosSimulatorArm64()
+    macosX64()
+    macosArm64()
+    mingwX64()
+    linuxX64()
+    linuxArm64()
+    js {
+        browser()
+        nodejs()
+    }
+    @OptIn(ExperimentalWasmDsl::class)
+    wasmJs() {
+        browser()
+        nodejs()
+    }
+
+    // Suppress Beta warning for expect/actual classes across all targets
+    targets.configureEach {
+        compilations.configureEach {
+            compilerOptions.configure {
+                freeCompilerArgs.add("-Xexpect-actual-classes")
+            }
+        }
+    }
+
+    sourceSets {
+        all {
+            languageSettings.optIn("kotlinx.coroutines.ExperimentalCoroutinesApi")
+            languageSettings.optIn("kotlin.ExperimentalUnsignedTypes")
+            // Correct opt-in markers for coroutines
+            languageSettings.optIn("kotlinx.coroutines.DelicateCoroutinesApi")
+            languageSettings.optIn("kotlin.contracts.ExperimentalContracts")
+            languageSettings.optIn("kotlinx.coroutines.FlowPreview")
+        }
+
+        val commonMain by getting {
+            kotlin.srcDir("$buildDir/generated/buildConfig/commonMain/kotlin")
+            dependencies {
+                implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.8.1")
+                //put your multiplatform dependencies here
+                api(libs.kotlinx.coroutines.core)
+                api(libs.mp.bintools)
+                api("net.sergeych:mp_stools:1.5.2")
+            }
+        }
+        val commonTest by getting {
+            dependencies {
+                implementation(libs.kotlin.test)
+                implementation(libs.kotlinx.coroutines.test)
+            }
+        }
+    }
+}
+
+android {
+    namespace = "org.jetbrains.kotlinx.multiplatform.library.template"
+    compileSdk = libs.versions.android.compileSdk.get().toInt()
+    defaultConfig {
+        minSdk = libs.versions.android.minSdk.get().toInt()
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+}
+dependencies {
+    implementation(libs.firebase.crashlytics.buildtools)
+    implementation(libs.compiler)
+}
+
+publishing {
+    val mavenToken by lazy {
+        File("${System.getProperty("user.home")}/.gitea_token").readText()
+    }
+    repositories {
+        maven {
+            credentials(HttpHeaderCredentials::class) {
+                name = "Authorization"
+                value = mavenToken
+            }
+            url = uri("https://gitea.sergeych.net/api/packages/SergeychWorks/maven")
+            authentication {
+                create("Authorization", HttpHeaderAuthentication::class)
+            }
+        }
+    }
+}
+
+// Ensure JVM test stdout is visible and runs are single-threaded for stable timings
+tasks.withType<org.gradle.api.tasks.testing.Test> {
+    testLogging {
+        showStandardStreams = true
+    }
+    maxParallelForks = 1
+
+    // Benchmarks toggle: disabled by default, enable when optimizing locally.
+    // Enable via any of the following:
+    //  - Gradle property:  ./gradlew :lynglib:jvmTest -Pbenchmarks=true
+    //  - JVM system prop:  ./gradlew :lynglib:jvmTest -Dbenchmarks=true
+    //  - Environment var:  BENCHMARKS=true ./gradlew :lynglib:jvmTest
+    val benchmarksEnabled: Boolean = run {
+        val p = (project.findProperty("benchmarks") as String?)?.toBooleanStrictOrNull()
+        val s = System.getProperty("benchmarks")?.lowercase()?.let { it == "true" || it == "1" || it == "yes" }
+        val e = System.getenv("BENCHMARKS")?.lowercase()?.let { it == "true" || it == "1" || it == "yes" }
+        p ?: s ?: e ?: false
+    }
+
+    // Make the flag visible inside tests if they want to branch on it
+    systemProperty("LYNG_BENCHMARKS", benchmarksEnabled.toString())
+
+    if (!benchmarksEnabled) {
+        // Exclude all JVM tests whose class name ends with or contains BenchmarkTest
+        // This keeps CI fast and avoids noisy timing logs by default.
+        filter {
+            excludeTestsMatching("*BenchmarkTest")
+            // Also guard against alternative naming
+            excludeTestsMatching("*Bench*Test")
+            // Exclude A/B performance tests unless explicitly enabled
+            excludeTestsMatching("*ABTest")
+            // Exclude stress/perf soak tests
+            excludeTestsMatching("*Stress*Test")
+            // Exclude allocation profiling tests by default
+            excludeTestsMatching("*AllocationProfileTest")
+        }
+        logger.lifecycle("[tests] Benchmarks are DISABLED. To enable: -Pbenchmarks=true or -Dbenchmarks=true or set BENCHMARKS=true")
+    } else {
+        logger.lifecycle("[tests] Benchmarks are ENABLED: *BenchmarkTest will run")
+    }
+}
+
+//mavenPublishing {
+//    publishToMavenCentral(SonatypeHost.CENTRAL_PORTAL)
+//
+//    signAllPublications()
+//
+//    coordinates(group.toString(), "library", version.toString())
+//
+//    pom {
+//        name = "Lyng language"
+//        description = "Kotlin-bound scripting loanguage"
+//        inceptionYear = "2025"
+////        url = "https://sergeych.net"
+//        licenses {
+//            license {
+//                name = "XXX"
+//                url = "YYY"
+//                distribution = "ZZZ"
+//            }
+//        }
+//        developers {
+//            developer {
+//                id = "XXX"
+//                name = "YYY"
+//                url = "ZZZ"
+//            }
+//        }
+//        scm {
+//            url = "XXX"
+//            connection = "YYY"
+//            developerConnection = "ZZZ"
+//        }
+//    }
+//}

lynglib/src/androidMain/kotlin/net/sergeych/lyng/ArgBuilderAndroid.kt

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package net.sergeych.lyng
+
+import net.sergeych.lyng.obj.Obj
+
+actual object ArgBuilderProvider {
+    private val tl = object : ThreadLocal<AndroidArgsBuilder>() {
+        override fun initialValue(): AndroidArgsBuilder = AndroidArgsBuilder()
+    }
+    actual fun acquire(): ArgsBuilder = tl.get()
+}
+
+private class AndroidArgsBuilder : ArgsBuilder {
+    private val buf: ArrayList<Obj> = ArrayList(8)
+
+    override fun reset(expectedSize: Int) {
+        buf.clear()
+        if (expectedSize > 0) buf.ensureCapacity(expectedSize)
+    }
+
+    override fun add(v: Obj) { buf.add(v) }
+
+    override fun addAll(vs: List<Obj>) {
+        if (vs.isNotEmpty()) {
+            buf.ensureCapacity(buf.size + vs.size)
+            buf.addAll(vs)
+        }
+    }
+
+    override fun build(tailBlockMode: Boolean): Arguments = Arguments(buf.toList(), tailBlockMode)
+
+    override fun release() { /* no-op, ThreadLocal keeps buffer */ }
+}

lynglib/src/androidMain/kotlin/net/sergeych/lyng/PerfDefaults.android.kt

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package net.sergeych.lyng
+
+actual object PerfDefaults {
+    actual val LOCAL_SLOT_PIC: Boolean = true
+    actual val EMIT_FAST_LOCAL_REFS: Boolean = true
+
+    actual val ARG_BUILDER: Boolean = true
+    actual val SKIP_ARGS_ON_NULL_RECEIVER: Boolean = true
+    actual val SCOPE_POOL: Boolean = false
+
+    actual val FIELD_PIC: Boolean = true
+    actual val METHOD_PIC: Boolean = true
+    actual val FIELD_PIC_SIZE_4: Boolean = false
+    actual val METHOD_PIC_SIZE_4: Boolean = false
+    actual val PIC_ADAPTIVE_2_TO_4: Boolean = false
+    actual val PIC_ADAPTIVE_METHODS_ONLY: Boolean = false
+    actual val PIC_ADAPTIVE_HEURISTIC: Boolean = false
+
+    actual val PIC_DEBUG_COUNTERS: Boolean = false
+
+    actual val PRIMITIVE_FASTOPS: Boolean = true
+    actual val RVAL_FASTPATH: Boolean = true
+    // Regex caching aligns with JVM behavior on Android (Dalvik/ART)
+    actual val REGEX_CACHE: Boolean = true
+    actual val ARG_SMALL_ARITY_12: Boolean = false
+    actual val INDEX_PIC_SIZE_4: Boolean = false
+    actual val RANGE_FAST_ITER: Boolean = false
+}

lynglib/src/androidMain/kotlin/net/sergeych/lyng/ScopePoolAndroid.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package net.sergeych.lyng
+
+import net.sergeych.lyng.obj.Obj
+import net.sergeych.lyng.obj.ObjVoid
+
+/**
+ * Android actual: per-thread scope frame pool backed by ThreadLocal.
+ */
+actual object ScopePool {
+    private const val MAX_POOL_SIZE = 64
+    private val threadLocalPool: ThreadLocal<ArrayDeque<Scope>?> = ThreadLocal()
+
+    private fun pool(): ArrayDeque<Scope> {
+        var p = threadLocalPool.get()
+        if (p == null) {
+            p = ArrayDeque<Scope>(MAX_POOL_SIZE)
+            threadLocalPool.set(p)
+        }
+        return p
+    }
+
+    actual fun borrow(parent: Scope, args: Arguments, pos: Pos, thisObj: Obj): Scope {
+        val pool = pool()
+        val s = if (pool.isNotEmpty()) pool.removeLast() else Scope(parent, args, pos, thisObj)
+        if (s.parent !== parent || s.args !== args || s.pos !== pos || s.thisObj !== thisObj) {
+            s.resetForReuse(parent, args, pos, thisObj)
+        } else {
+            s.frameId = nextFrameId()
+        }
+        return s
+    }
+
+    actual fun release(scope: Scope) {
+        val pool = pool()
+        scope.resetForReuse(parent = null, args = Arguments.EMPTY, pos = Pos.builtIn, thisObj = ObjVoid)
+        if (pool.size < MAX_POOL_SIZE) pool.addLast(scope)
+    }
+}

lynglib/src/commonMain/kotlin/net/sergeych/lyng/AccessType.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package net.sergeych.lyng
+
+enum class AccessType(val isMutable: Boolean) {
+    Val(false), Var(true),
+
+    @Suppress("unused")
+    Initialization(false)
+}

lynglib/src/commonMain/kotlin/net/sergeych/lyng/ArgBuilder.kt

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package net.sergeych.lyng
+
+import net.sergeych.lyng.obj.Obj
+
+/**
+ * Expect/actual API for an arguments builder that can reuse buffers on JVM to reduce allocations.
+ * Default (non-JVM) implementation just allocates fresh collections and has no pooling.
+ */
+expect object ArgBuilderProvider {
+    fun acquire(): ArgsBuilder
+}
+
+interface ArgsBuilder {
+    /** Prepare the builder for a new build, optionally hinting capacity. */
+    fun reset(expectedSize: Int = 0)
+    fun add(v: Obj)
+    fun addAll(vs: List<Obj>)
+    /** Build immutable [Arguments] snapshot from the current buffer. */
+    fun build(tailBlockMode: Boolean): Arguments
+    /** Return builder to pool/reset state. Safe to no-op on non-JVM. */
+    fun release()
+}