update version, site and docs

docs/whats_new.md

@@ -1,7 +1,7 @@
 # What's New in Lyng
 
 This document highlights the latest additions and improvements to the Lyng language and its ecosystem.
-For a programmer-focused migration summary, see `docs/whats_new_1_3.md`.
+For a programmer-focused migration summary, see `docs/whats_new_1_5.md`.
 
 ## Language Features
 
@@ -102,7 +102,7 @@ Singleton objects are declared using the `object` keyword. They provide a conven
 
 ```lyng
 object Config {
-    val version = "1.2.3"
+    val version = "1.5.0-SNAPSHOT"
     fun show() = println("Config version: " + version)
 }
 

docs/whats_new_1_5.md

@@ -0,0 +1,93 @@
+# What's New in Lyng 1.5 (vs 1.3.* / master)
+
+This document summarizes the significant changes and new features introduced in the 1.5.0-SNAPSHOT development cycle.
+
+## Highlights
+
+- **The `return` Statement**: Added support for local and non-local returns using labels.
+- **Abstract Classes and Interfaces**: Full support for `abstract` members and the `interface` keyword.
+- **Class Properties with Accessors**: Define `val` and `var` properties with custom `get()` and `set()`.
+- **Restricted Setter Visibility**: Use `private set` and `protected set` on fields and properties.
+- **Late-initialized `val`**: Support for `val` fields that are initialized in `init` blocks or class bodies.
+- **Named Arguments and Splats**: Improved call-site readability with `name: value` and map-based splats.
+- **Refined Visibility**: Improved `protected` access and `closed` modifier for better encapsulation.
+
+## Language Features
+
+### The `return` Statement
+You can now exit from the innermost enclosing callable (function or lambda) using `return`. Lyng also supports non-local returns to outer scopes using labels.
+
+```lyng
+fun findFirst<T>(list: Iterable<T>, predicate: (T)->Bool): T? {
+    list.forEach {
+        if (predicate(it)) return@findFirst it
+    }
+    null
+}
+```
+
+### Abstract Classes and Interfaces
+Lyng now supports the `abstract` modifier for classes and their members. `interface` is introduced as a synonym for `abstract class`, allowing for rich multi-inheritance patterns.
+
+```lyng
+interface Shape {
+    abstract val area: Real
+    fun describe() = "Area: %g"(area)
+}
+
+class Circle(val radius: Real) : Shape {
+    override val area get = Math.PI * radius * radius
+}
+```
+
+### Class Properties with Accessors
+Properties can now have custom getters and setters. They do not have automatic backing fields, making them perfect for computed values or delegation.
+
+```lyng
+class Rectangle(var width: Real, var height: Real) {
+    val area: Real get() = width * height
+    
+    var squareSize: Real
+        get() = area
+        set(v) {
+            width = sqrt(v)
+            height = width
+        }
+}
+```
+
+### Named Arguments and Named Splats
+Improve call-site clarity by specifying argument names. You can also expand a Map into named arguments using the splat operator.
+
+```lyng
+fun configure(timeout: Int, retry: Int = 3) { ... }
+
+configure(timeout: 5000, retry: 5)
+val options = { timeout: 1000, retry: 1 }
+configure(...options)
+```
+
+### Modern Operators
+The `?=` operator allows for concise "assign if null" logic.
+
+```lyng
+var cache: Map? = null
+cache ?= { "status": "ok" } // Only assigns if cache is null
+```
+
+## Tooling and IDE
+
+- **IDEA Plugin**: Significant improvements to autocompletion, documentation tooltips, and natural language support (Grazie integration).
+- **CLI**: The `lyng fmt` command is now a first-class tool for formatting code with various options like `--check` and `--in-place`.
+- **Performance**: Ongoing optimizations in the bytecode VM and compiler for faster execution and smaller footprint.
+
+## Migration Guide (from 1.3.*)
+
+1. **Check Visibility**: Refined `protected` and `private` rules may catch previously undetected invalid accesses.
+2. **Override Keyword**: Ensure all members that override ancestor declarations are marked with the `override` keyword (now mandatory).
+3. **Return in Shorthand**: Remember that `return` is forbidden in `=` shorthand functions; use block syntax if you need early exit.
+
+## References
+- `docs/OOP.md`
+- `docs/return_statement.md`
+- `docs/tutorial.md`