repeat-forever loop is now replaced by label+jump

codeGenCpu6502/src/prog8/codegen/cpu6502/AsmGen.kt

@@ -582,14 +582,7 @@ class AsmGen(internal val program: Program,
         loopEndLabels.push(endLabel)
 
         when (stmt.iterations) {
-            null -> {
-                // endless loop
-                val repeatLabel = makeLabel("repeat")
-                out(repeatLabel)
-                translate(stmt.body)
-                jmp(repeatLabel)
-                out(endLabel)
-            }
+            null -> throw AssemblyError("repeat-forever loop should have been replaced by label+jump")
             is NumericLiteral -> {
                 val iterations = (stmt.iterations as NumericLiteral).number.toInt()
                 when {

compiler/src/prog8/compiler/astprocessing/CodeDesugarer.kt

@@ -15,6 +15,7 @@ import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
 import prog8.compilerinterface.IErrorReporter
 
+private var generatedLabelSequenceNumber: Int = 0
 
 internal class CodeDesugarer(val program: Program, private val errors: IErrorReporter) : AstWalker() {
 
@@ -27,9 +28,9 @@ internal class CodeDesugarer(val program: Program, private val errors: IErrorRep
     // - replace 'break' statements by a goto + generated after label.
     // - replace while and do-until loops by just jumps.
     // - replace peek() and poke() by direct memory accesses.
+    // - repeat-forever loops replaced by label+jump.
 
 
-    private var generatedLabelSequenceNumber: Int = 0
     private val generatedLabelPrefix = "prog8_label_"
 
     private fun makeLabel(postfix: String, position: Position): Label {
@@ -137,4 +138,17 @@ _after:
         }
         return noModifications
     }
+
+    override fun after(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> {
+        if(repeatLoop.iterations==null) {
+            val label = makeLabel("repeat", repeatLoop.position)
+            val jump = jumpLabel(label)
+            return listOf(
+                IAstModification.InsertFirst(label, repeatLoop.body),
+                IAstModification.InsertLast(jump, repeatLoop.body),
+                IAstModification.ReplaceNode(repeatLoop, repeatLoop.body, parent)
+            )
+        }
+        return noModifications
+    }
 }

compiler/test/TestScoping.kt

@@ -37,7 +37,7 @@ class TestScoping: FunSpec({
         val src = """
             main {
                 sub start() {
-                    repeat {
+                    repeat 10 {
                         ubyte xx = 99
                         xx++
                     }
@@ -91,7 +91,7 @@ class TestScoping: FunSpec({
             iflabel:
                     }
         
-                    repeat {
+                    repeat 10 {
                         addr = &iflabel
                         addr = &labelinside
                         addr = &labeloutside