From 514ad96148c046e69ad0339fa2e7de6321f1f76e Mon Sep 17 00:00:00 2001
From: sergeych <real.sergeych@gmail.com>
Date: Mon, 5 Jan 2026 11:14:05 +0100
Subject: [PATCH] AccessException -< IllegalAccessException; added TODO() and
 NotImplementedException

---
 docs/Testing.md                               | 16 +++++++--
 .../kotlin/net/sergeych/lyng/Script.kt        | 34 +++++++++++++++----
 .../kotlin/net/sergeych/lyng/obj/Obj.kt       |  8 ++---
 .../net/sergeych/lyng/obj/ObjException.kt     | 12 ++++---
 .../net/sergeych/lyng/obj/ObjInstance.kt      | 28 +++++++--------
 .../kotlin/net/sergeych/lyng/obj/ObjRef.kt    | 14 ++++----
 lynglib/src/commonTest/kotlin/OOTest.kt       |  6 ++--
 lynglib/src/commonTest/kotlin/ScriptTest.kt   | 30 +++++++++++++++-
 lynglib/stdlib/lyng/root.lyng                 |  1 +
 9 files changed, 107 insertions(+), 42 deletions(-)

diff --git a/docs/Testing.md b/docs/Testing.md
index b344293..34abca8 100644
--- a/docs/Testing.md
+++ b/docs/Testing.md
@@ -93,8 +93,6 @@ If we want to evaluate the message lazily:
 
 In this case, formatting will only occur if the condition is not met.
 
-
-
 ### `check`
 
     check(condition, message="check failed")
@@ -107,3 +105,17 @@ With lazy message evaluation:
 
 In this case, formatting will only occur if the condition is not met.
 
+### TODO
+
+It is easy to mark some code and make it throw a special exception at cone with:
+
+    TODO()
+
+or
+
+    TODO("some message")
+
+It raises an `NotImplementedException` with the given message. You can catch it
+as any other exception when necessary.
+
+Many IDE and editors have built-in support for marking code with TODOs.
diff --git a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/Script.kt b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/Script.kt
index 3e54926..0fe4726 100644
--- a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/Script.kt
+++ b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/Script.kt
@@ -21,6 +21,7 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.yield
 import net.sergeych.lyng.Script.Companion.defaultImportManager
 import net.sergeych.lyng.miniast.addConstDoc
+import net.sergeych.lyng.miniast.addFnDoc
 import net.sergeych.lyng.miniast.addVoidFnDoc
 import net.sergeych.lyng.miniast.type
 import net.sergeych.lyng.obj.*
@@ -204,18 +205,32 @@ class Script(
                         )
                     )
             }
-            addFn("assertThrows") {
+            addFnDoc(
+                "assertThrows",
+                doc = """
+                    Asserts that the provided code block throws an exception, with or without exception: 
+                    ```lyng
+                        assertThrows { /* ode */ }
+                        assertThrows(IllegalArgumentException) { /* code */ }
+                    ```
+                    If an expected exception class is provided,
+                    it checks that the thrown exception is of that class. If no expected class is provided, any exception
+                    will be accepted.
+                """.trimIndent()
+            ) {
                 val code: Statement
                 val expectedClass: ObjClass?
-                when(args.size) {
+                when (args.size) {
                     1 -> {
                         code = requiredArg<Statement>(0)
                         expectedClass = null
                     }
+
                     2 -> {
                         code = requiredArg<Statement>(1)
                         expectedClass = requiredArg<ObjClass>(0)
                     }
+
                     else -> raiseIllegalArgument("Expected 1 or 2 arguments, got ${args.size}")
                 }
                 val result = try {
@@ -226,10 +241,15 @@ class Script(
                 } catch (_: ScriptError) {
                     ObjNull
                 }
-                if( result == null ) raiseError(ObjAssertionFailedException(this, "Expected exception but nothing was thrown"))
+                if (result == null) raiseError(
+                    ObjAssertionFailedException(
+                        this,
+                        "Expected exception but nothing was thrown"
+                    )
+                )
                 expectedClass?.let {
-                    if( result !is ObjException)
-                        raiseError("Expected $expectedClass, got $result")
+                    if (result !is ObjException)
+                        raiseError("Expected $expectedClass, got non-lyng exception $result")
                     if (result.exceptionClass != expectedClass) {
                         raiseError("Expected $expectedClass, got ${result.exceptionClass}")
                     }
@@ -255,7 +275,7 @@ class Script(
                 val condition = requiredArg<ObjBool>(0)
                 if (!condition.value) {
                     var message = args.list.getOrNull(1)
-                    if( message is Statement ) message = message.execute(this)
+                    if (message is Statement) message = message.execute(this)
                     raiseIllegalArgument(message?.toString() ?: "requirement not met")
                 }
                 ObjVoid
@@ -264,7 +284,7 @@ class Script(
                 val condition = requiredArg<ObjBool>(0)
                 if (!condition.value) {
                     var message = args.list.getOrNull(1)
-                    if( message is Statement ) message = message.execute(this)
+                    if (message is Statement) message = message.execute(this)
                     raiseIllegalState(message?.toString() ?: "check failed")
                 }
                 ObjVoid
diff --git a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/Obj.kt b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/Obj.kt
index a209ac6..482baec 100644
--- a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/Obj.kt
+++ b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/Obj.kt
@@ -93,7 +93,7 @@ open class Obj {
                 val decl = rec.declaringClass ?: cls
                 val caller = scope.currentClassCtx
                 if (!canAccessMember(rec.visibility, decl, caller))
-                    scope.raiseError(ObjAccessException(scope, "can't invoke ${name}: not visible (declared in ${decl.className}, caller ${caller?.className ?: "?"})"))
+                    scope.raiseError(ObjIllegalAccessException(scope, "can't invoke ${name}: not visible (declared in ${decl.className}, caller ${caller?.className ?: "?"})"))
                 val saved = scope.currentClassCtx
                 scope.currentClassCtx = decl
                 try {
@@ -117,7 +117,7 @@ open class Obj {
                     val decl = rec.declaringClass ?: cls
                     val caller = scope.currentClassCtx
                     if (!canAccessMember(rec.visibility, decl, caller))
-                        scope.raiseError(ObjAccessException(scope, "can't invoke ${name}: not visible (declared in ${decl.className}, caller ${caller?.className ?: "?"})"))
+                        scope.raiseError(ObjIllegalAccessException(scope, "can't invoke ${name}: not visible (declared in ${decl.className}, caller ${caller?.className ?: "?"})"))
                     val saved = scope.currentClassCtx
                     scope.currentClassCtx = decl
                     try {
@@ -387,7 +387,7 @@ open class Obj {
         val caller = scope.currentClassCtx
         // Check visibility for non-property members here if they weren't checked before
         if (!canAccessMember(obj.visibility, decl, caller))
-            scope.raiseError(ObjAccessException(scope, "can't access field ${name}: not visible (declared in ${decl?.className ?: "?"}, caller ${caller?.className ?: "?"})"))
+            scope.raiseError(ObjIllegalAccessException(scope, "can't access field ${name}: not visible (declared in ${decl?.className ?: "?"}, caller ${caller?.className ?: "?"})"))
         return obj
     }
 
@@ -424,7 +424,7 @@ open class Obj {
         val decl = field.declaringClass
         val caller = scope.currentClassCtx
         if (!canAccessMember(field.effectiveWriteVisibility, decl, caller))
-            scope.raiseError(ObjAccessException(scope, "can't assign field ${name}: not visible (declared in ${decl?.className ?: "?"}, caller ${caller?.className ?: "?"})"))
+            scope.raiseError(ObjIllegalAccessException(scope, "can't assign field ${name}: not visible (declared in ${decl?.className ?: "?"}, caller ${caller?.className ?: "?"})"))
         if (field.value is ObjProperty) {
             (field.value as ObjProperty).callSetter(scope, this, newValue, decl)
         } else if (field.isMutable) field.value = newValue else scope.raiseError("can't assign to read-only field: $name")
diff --git a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjException.kt b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjException.kt
index e3a3f01..065e79a 100644
--- a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjException.kt
+++ b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjException.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ * Copyright 2026 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.
@@ -191,11 +191,12 @@ open class ObjException(
                 "IllegalAssignmentException",
                 "SymbolNotDefinedException",
                 "IterationEndException",
-                "AccessException",
+                "IllegalAccessException",
                 "UnknownException",
                 "NotFoundException",
                 "IllegalOperationException",
                 "UnsetException",
+                "NotImplementedException",
                 "SyntaxError"
             )) {
                 scope.addConst(name, getOrCreateExceptionClass(name))
@@ -236,8 +237,8 @@ class ObjSymbolNotDefinedException(scope: Scope, message: String = "symbol is no
 class ObjIterationFinishedException(scope: Scope) :
     ObjException("IterationEndException", scope, "iteration finished")
 
-class ObjAccessException(scope: Scope, message: String = "access not allowed error") :
-    ObjException("AccessException", scope, message)
+class ObjIllegalAccessException(scope: Scope, message: String = "access not allowed error") :
+    ObjException("IllegalAccessException", scope, message)
 
 class ObjUnknownException(scope: Scope, message: String = "access not allowed error") :
     ObjException("UnknownException", scope, message)
@@ -250,3 +251,6 @@ class ObjNotFoundException(scope: Scope, message: String = "not found") :
 
 class ObjUnsetException(scope: Scope, message: String = "property is unset (not initialized)") :
     ObjException("UnsetException", scope, message)
+
+class ObjNotImplementedException(scope: Scope, message: String = "not implemented") :
+    ObjException("NotImplementedException", scope, message)
diff --git a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjInstance.kt b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjInstance.kt
index 2504fbd..eefc376 100644
--- a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjInstance.kt
+++ b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjInstance.kt
@@ -40,7 +40,7 @@ class ObjInstance(override val objClass: ObjClass) : Obj() {
                 val caller = scope.currentClassCtx
                 if (!canAccessMember(rec.visibility, decl, caller))
                     scope.raiseError(
-                        ObjAccessException(
+                        ObjIllegalAccessException(
                             scope,
                             "can't access field $name (declared in ${decl?.className ?: "?"})"
                         )
@@ -81,7 +81,7 @@ class ObjInstance(override val objClass: ObjClass) : Obj() {
                 val caller = scope.currentClassCtx
                 if (!canAccessMember(rec.visibility, declaring, caller))
                     scope.raiseError(
-                        ObjAccessException(
+                        ObjIllegalAccessException(
                             scope,
                             "can't access field $name (declared in ${declaring?.className ?: "?"})"
                         )
@@ -104,7 +104,7 @@ class ObjInstance(override val objClass: ObjClass) : Obj() {
             if (scope.thisObj !== this || scope.currentClassCtx == null) {
                 val caller = scope.currentClassCtx
                 if (!canAccessMember(f.effectiveWriteVisibility, decl, caller))
-                    ObjAccessException(
+                    ObjIllegalAccessException(
                         scope,
                         "can't assign to field $name (declared in ${decl?.className ?: "?"})"
                     ).raise()
@@ -139,7 +139,7 @@ class ObjInstance(override val objClass: ObjClass) : Obj() {
             if (scope.thisObj !== this || scope.currentClassCtx == null) {
                 val caller = scope.currentClassCtx
                 if (!canAccessMember(rec.effectiveWriteVisibility, declaring, caller))
-                    ObjAccessException(
+                    ObjIllegalAccessException(
                         scope,
                         "can't assign to field $name (declared in ${declaring?.className ?: "?"})"
                     ).raise()
@@ -168,7 +168,7 @@ class ObjInstance(override val objClass: ObjClass) : Obj() {
                 val caller = scope.currentClassCtx ?: if (scope.thisObj === this) objClass else null
                 if (!canAccessMember(rec.visibility, decl, caller))
                     scope.raiseError(
-                        ObjAccessException(
+                        ObjIllegalAccessException(
                             scope,
                             "can't invoke method $name (declared in ${decl?.className ?: "?"})"
                         )
@@ -189,7 +189,7 @@ class ObjInstance(override val objClass: ObjClass) : Obj() {
                         val caller = scope.currentClassCtx ?: if (scope.thisObj === this) objClass else null
                         if (!canAccessMember(rec.visibility, decl, caller))
                             scope.raiseError(
-                                ObjAccessException(
+                                ObjIllegalAccessException(
                                     scope,
                                     "can't invoke method $name (declared in ${decl?.className ?: "?"})"
                                 )
@@ -319,7 +319,7 @@ class ObjQualifiedView(val instance: ObjInstance, private val startClass: ObjCla
             val decl = rec.declaringClass ?: startClass
             val caller = scope.currentClassCtx
             if (!canAccessMember(rec.visibility, decl, caller))
-                scope.raiseError(ObjAccessException(scope, "can't access field $name (declared in ${decl.className})"))
+                scope.raiseError(ObjIllegalAccessException(scope, "can't access field $name (declared in ${decl.className})"))
             return rec
         }
         // Then try instance locals (unmangled) only if startClass is the dynamic class itself
@@ -329,7 +329,7 @@ class ObjQualifiedView(val instance: ObjInstance, private val startClass: ObjCla
                 val caller = scope.currentClassCtx
                 if (!canAccessMember(rec.visibility, decl, caller))
                     scope.raiseError(
-                        ObjAccessException(
+                        ObjIllegalAccessException(
                             scope,
                             "can't access field $name (declared in ${decl?.className ?: "?"})"
                         )
@@ -342,7 +342,7 @@ class ObjQualifiedView(val instance: ObjInstance, private val startClass: ObjCla
         val decl = r.declaringClass ?: startClass
         val caller = scope.currentClassCtx
         if (!canAccessMember(r.visibility, decl, caller))
-            scope.raiseError(ObjAccessException(scope, "can't access field $name (declared in ${decl.className})"))
+            scope.raiseError(ObjIllegalAccessException(scope, "can't access field $name (declared in ${decl.className})"))
         return when (val value = r.value) {
             is net.sergeych.lyng.Statement -> ObjRecord(
                 value.execute(
@@ -364,7 +364,7 @@ class ObjQualifiedView(val instance: ObjInstance, private val startClass: ObjCla
             val decl = f.declaringClass ?: startClass
             val caller = scope.currentClassCtx
             if (!canAccessMember(f.effectiveWriteVisibility, decl, caller))
-                ObjAccessException(
+                ObjIllegalAccessException(
                     scope,
                     "can't assign to field $name (declared in ${decl.className})"
                 ).raise()
@@ -378,7 +378,7 @@ class ObjQualifiedView(val instance: ObjInstance, private val startClass: ObjCla
                 val decl = f.declaringClass ?: instance.objClass.findDeclaringClassOf(name)
                 val caller = scope.currentClassCtx
                 if (!canAccessMember(f.effectiveWriteVisibility, decl, caller))
-                    ObjAccessException(
+                    ObjIllegalAccessException(
                         scope,
                         "can't assign to field $name (declared in ${decl?.className ?: "?"})"
                     ).raise()
@@ -391,7 +391,7 @@ class ObjQualifiedView(val instance: ObjInstance, private val startClass: ObjCla
         val decl = r.declaringClass ?: startClass
         val caller = scope.currentClassCtx
         if (!canAccessMember(r.effectiveWriteVisibility, decl, caller))
-            ObjAccessException(scope, "can't assign to field $name (declared in ${decl.className})").raise()
+            ObjIllegalAccessException(scope, "can't assign to field $name (declared in ${decl.className})").raise()
         if (!r.isMutable) scope.raiseError("can't assign to read-only field: $name")
         if (r.value.assign(scope, newValue) == null) r.value = newValue
     }
@@ -407,7 +407,7 @@ class ObjQualifiedView(val instance: ObjInstance, private val startClass: ObjCla
             val decl = rec.declaringClass ?: startClass
             val caller = scope.currentClassCtx
             if (!canAccessMember(rec.visibility, decl, caller))
-                scope.raiseError(ObjAccessException(scope, "can't invoke method $name (declared in ${decl.className})"))
+                scope.raiseError(ObjIllegalAccessException(scope, "can't invoke method $name (declared in ${decl.className})"))
             val saved = instance.instanceScope.currentClassCtx
             instance.instanceScope.currentClassCtx = decl
             try {
@@ -423,7 +423,7 @@ class ObjQualifiedView(val instance: ObjInstance, private val startClass: ObjCla
                 val caller = scope.currentClassCtx
                 if (!canAccessMember(rec.visibility, decl, caller))
                     scope.raiseError(
-                        ObjAccessException(
+                        ObjIllegalAccessException(
                             scope,
                             "can't invoke method $name (declared in ${decl?.className ?: "?"})"
                         )
diff --git a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjRef.kt b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjRef.kt
index 6158696..89467c7 100644
--- a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjRef.kt
+++ b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjRef.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ * Copyright 2026 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.
@@ -595,7 +595,7 @@ class FieldRef(
                             val scope0 = (obj as ObjClass).classScope!!
                             val r0 = scope0.getSlotRecord(capturedIdx)
                             if (!r0.visibility.isPublic)
-                                sc.raiseError(ObjAccessException(sc, "can't access non-public field $name"))
+                                sc.raiseError(ObjIllegalAccessException(sc, "can't access non-public field $name"))
                             r0
                         }
                     } else {
@@ -631,7 +631,7 @@ class FieldRef(
                     // visibility/mutability checks
                     if (!rec.isMutable) scope.raiseError(ObjIllegalAssignmentException(scope, "can't reassign val $name"))
                     if (!rec.visibility.isPublic)
-                        scope.raiseError(ObjAccessException(scope, "can't access non-public field $name"))
+                        scope.raiseError(ObjIllegalAccessException(scope, "can't access non-public field $name"))
                     if (rec.value.assign(scope, newValue) == null) rec.value = newValue
                     return
                 }
@@ -1195,7 +1195,7 @@ class MethodCallRef(
                         mKey1 = key; mVer1 = ver; mInvoker1 = { obj, sc, a ->
                             val inst = obj as ObjInstance
                             if (!visibility.isPublic && !canAccessMember(visibility, hierarchyMember.declaringClass ?: inst.objClass, sc.currentClassCtx))
-                                sc.raiseError(ObjAccessException(sc, "can't invoke non-public method $name"))
+                                sc.raiseError(ObjIllegalAccessException(sc, "can't invoke non-public method $name"))
                             callable.invoke(inst.instanceScope, inst, a)
                         }
                     } else {
@@ -1467,7 +1467,7 @@ class BoundLocalVarRef(
         scope.pos = atPos
         val rec = scope.getSlotRecord(slot)
         if (rec.declaringClass != null && !canAccessMember(rec.visibility, rec.declaringClass, scope.currentClassCtx))
-            scope.raiseError(ObjAccessException(scope, "private field access"))
+            scope.raiseError(ObjIllegalAccessException(scope, "private field access"))
         return rec
     }
 
@@ -1475,7 +1475,7 @@ class BoundLocalVarRef(
         scope.pos = atPos
         val rec = scope.getSlotRecord(slot)
         if (rec.declaringClass != null && !canAccessMember(rec.visibility, rec.declaringClass, scope.currentClassCtx))
-            scope.raiseError(ObjAccessException(scope, "private field access"))
+            scope.raiseError(ObjIllegalAccessException(scope, "private field access"))
         return rec.value
     }
 
@@ -1483,7 +1483,7 @@ class BoundLocalVarRef(
         scope.pos = atPos
         val rec = scope.getSlotRecord(slot)
         if (rec.declaringClass != null && !canAccessMember(rec.visibility, rec.declaringClass, scope.currentClassCtx))
-            scope.raiseError(ObjAccessException(scope, "private field access"))
+            scope.raiseError(ObjIllegalAccessException(scope, "private field access"))
         if (!rec.isMutable) scope.raiseError("Cannot assign to immutable value")
         rec.value = newValue
     }
diff --git a/lynglib/src/commonTest/kotlin/OOTest.kt b/lynglib/src/commonTest/kotlin/OOTest.kt
index ec38098..b9ed415 100644
--- a/lynglib/src/commonTest/kotlin/OOTest.kt
+++ b/lynglib/src/commonTest/kotlin/OOTest.kt
@@ -488,7 +488,7 @@ class OOTest {
                 fun setValue(newValue) { y = newValue }
             }
             assertEquals(100, A().y)
-            assertThrows(AccessException) { A().y = 200 }
+            assertThrows(IllegalAccessException) { A().y = 200 }
             val a = A()
             a.setValue(200)
             assertEquals(200, a.y)
@@ -502,7 +502,7 @@ class OOTest {
             }
             val c = C(10)
             assertEquals(10, c.y)
-            assertThrows(AccessException) { c.y = 20 }
+            assertThrows(IllegalAccessException) { c.y = 20 }
             c.setBValue(30)
             assertEquals(30, c.y)
             
@@ -515,7 +515,7 @@ class OOTest {
             }
             val d = D()
             assertEquals(0, d.y)
-            assertThrows(AccessException) { d.y = 10 }
+            assertThrows(IllegalAccessException) { d.y = 10 }
             d.setY(20)
             assertEquals(20, d.y)
         """
diff --git a/lynglib/src/commonTest/kotlin/ScriptTest.kt b/lynglib/src/commonTest/kotlin/ScriptTest.kt
index 089ac03..63b43d2 100644
--- a/lynglib/src/commonTest/kotlin/ScriptTest.kt
+++ b/lynglib/src/commonTest/kotlin/ScriptTest.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ * Copyright 2026 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.
@@ -4532,4 +4532,32 @@ class ScriptTest {
         """.trimIndent())
     }
 
+//    @Test
+//    fun testUserClassExceptions() = runTest {
+//        eval("""
+//            val x = try { throw IllegalAccessException("test1") } catch { it }
+//            assertEquals("test1", x.message)
+//            assert( x is IllegalAccessException)
+//            assertThrows(IllegalAccessException) {   throw IllegalAccessException("test2") }
+//
+//            class X : Exception("test3")
+//            val y = try { throw X() } catch { it }
+//            println(y)
+//            assertEquals("test3", y.message)
+//            assert( y is X)
+//
+//        """.trimIndent())
+//    }
+
+    @Test
+    fun testTodo() = runTest {
+        eval("""
+            assertThrows(NotImplementedException) {
+                TODO()
+            }
+            val x = try { TODO("check me") } catch { it }
+            assertEquals("check me", x.message)
+        """.trimIndent())
+    }
+
 }
diff --git a/lynglib/stdlib/lyng/root.lyng b/lynglib/stdlib/lyng/root.lyng
index 5289520..0e3bafb 100644
--- a/lynglib/stdlib/lyng/root.lyng
+++ b/lynglib/stdlib/lyng/root.lyng
@@ -276,3 +276,4 @@ fun Exception.printStackTrace() {
 /* Compile this string into a regular expression. */
 val String.re get() = Regex(this)
 
+fun TODO(message=null) = throw NotImplementedException(message ?: "not implemented")