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Add iterator cancellation for bytecode for-in loops

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This commit is contained in:
Sergey Chernov 2026-01-29 06:47:27 +03:00
parent 0e069382a2
commit e346e7e56e
9 changed files with 215 additions and 40 deletions
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29
lynglib/src/commonMain/kotlin/net/sergeych/lyng/Compiler.kt
View File

@ -3401,26 +3401,15 @@ class Compiler(
val names = mutableListOf<String>()
pattern.forEachVariable { names.add(it) }
return object : Statement() {
override val pos: Pos = start
override suspend fun execute(context: Scope): Obj {
val value = initialExpression.execute(context)
for (name in names) {
context.addItem(name, true, ObjVoid, visibility, isTransient = isTransient)
}
pattern.setAt(start, context, value)
if (!isMutable) {
for (name in names) {
val rec = context.objects[name]!!
val immutableRec = rec.copy(isMutable = false)
context.objects[name] = immutableRec
context.localBindings[name] = immutableRec
context.updateSlotFor(name, immutableRec)
}
}
return ObjVoid
}
}
return DestructuringVarDeclStatement(
pattern,
names,
initialExpression,
isMutable,
visibility,
isTransient,
start
)
}
if (nextToken.type != Token.Type.ID)

49
lynglib/src/commonMain/kotlin/net/sergeych/lyng/DestructuringVarDeclStatement.kt Normal file
View File

@ -0,0 +1,49 @@
/*
* Copyright 2026 Sergey S. Chernov
*
* 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.ListLiteralRef
import net.sergeych.lyng.obj.Obj
import net.sergeych.lyng.obj.ObjVoid
class DestructuringVarDeclStatement(
val pattern: ListLiteralRef,
val names: List<String>,
val initializer: Statement,
val isMutable: Boolean,
val visibility: Visibility,
val isTransient: Boolean,
override val pos: Pos,
) : Statement() {
override suspend fun execute(context: Scope): Obj {
val value = initializer.execute(context)
for (name in names) {
context.addItem(name, true, ObjVoid, visibility, isTransient = isTransient)
}
pattern.setAt(pos, context, value)
if (!isMutable) {
for (name in names) {
val rec = context.objects[name]!!
val immutableRec = rec.copy(isMutable = false)
context.objects[name] = immutableRec
context.localBindings[name] = immutableRec
context.updateSlotFor(name, immutableRec)
}
}
return ObjVoid
}
}

86
lynglib/src/commonMain/kotlin/net/sergeych/lyng/bytecode/BytecodeCompiler.kt
View File

@ -17,6 +17,7 @@
package net.sergeych.lyng.bytecode
import net.sergeych.lyng.BlockStatement
import net.sergeych.lyng.DestructuringVarDeclStatement
import net.sergeych.lyng.ExpressionStatement
import net.sergeych.lyng.IfStatement
import net.sergeych.lyng.ParsedArgument
@ -69,6 +70,7 @@ class BytecodeCompiler(
val continueLabel: CmdBuilder.Label,
val breakFlagSlot: Int,
val resultSlot: Int?,
val hasIterator: Boolean,
)
fun compileStatement(name: String, stmt: net.sergeych.lyng.Statement): CmdFunction? {
@ -1973,6 +1975,7 @@ class BytecodeCompiler(
}
is BlockStatement -> emitBlock(target, true)
is VarDeclStatement -> emitVarDecl(target)
is DestructuringVarDeclStatement -> emitStatementEval(target)
is net.sergeych.lyng.ExtensionPropertyDeclStatement -> emitExtensionPropertyDecl(target)
is net.sergeych.lyng.ClassDeclStatement -> emitStatementEval(target)
is net.sergeych.lyng.FunctionDeclStatement -> emitStatementEval(target)
@ -2018,6 +2021,7 @@ class BytecodeCompiler(
}
is BlockStatement -> emitBlock(target, false)
is VarDeclStatement -> emitVarDecl(target)
is DestructuringVarDeclStatement -> emitStatementEval(target)
is net.sergeych.lyng.ExtensionPropertyDeclStatement -> emitExtensionPropertyDecl(target)
is net.sergeych.lyng.BreakStatement -> compileBreak(target)
is net.sergeych.lyng.ContinueStatement -> compileContinue(target)
@ -2202,6 +2206,7 @@ class BytecodeCompiler(
val iterSlot = allocSlot()
val iteratorId = builder.addConst(BytecodeConst.StringVal("iterator"))
builder.emit(Opcode.CALL_VIRTUAL, sourceObj.slot, iteratorId, 0, 0, iterSlot)
builder.emit(Opcode.ITER_PUSH, iterSlot)
val breakFlagSlot = allocSlot()
val falseId = builder.addConst(BytecodeConst.Bool(false))
@ -2235,7 +2240,14 @@ class BytecodeCompiler(
updateSlotTypeByName(stmt.loopVarName, SlotType.OBJ)
loopStack.addLast(
LoopContext(stmt.label, endLabel, continueLabel, breakFlagSlot, if (wantResult) resultSlot else null)
LoopContext(
stmt.label,
endLabel,
continueLabel,
breakFlagSlot,
if (wantResult) resultSlot else null,
hasIterator = true
)
)
val bodyValue = compileLoopBody(stmt.body, wantResult) ?: return null
loopStack.removeLast()
@ -2247,6 +2259,13 @@ class BytecodeCompiler(
builder.emit(Opcode.JMP, listOf(CmdBuilder.Operand.LabelRef(loopLabel)))
builder.mark(endLabel)
val afterPop = builder.label()
builder.emit(
Opcode.JMP_IF_TRUE,
listOf(CmdBuilder.Operand.IntVal(breakFlagSlot), CmdBuilder.Operand.LabelRef(afterPop))
)
builder.emit(Opcode.ITER_POP)
builder.mark(afterPop)
if (stmt.elseStatement != null) {
val afterElse = builder.label()
builder.emit(
@ -2316,7 +2335,14 @@ class BytecodeCompiler(
updateSlotType(loopSlotId, SlotType.INT)
updateSlotTypeByName(stmt.loopVarName, SlotType.INT)
loopStack.addLast(
LoopContext(stmt.label, endLabel, continueLabel, breakFlagSlot, if (wantResult) resultSlot else null)
LoopContext(
stmt.label,
endLabel,
continueLabel,
breakFlagSlot,
if (wantResult) resultSlot else null,
hasIterator = false
)
)
val bodyValue = compileLoopBody(stmt.body, wantResult) ?: return null
loopStack.removeLast()
@ -2375,7 +2401,14 @@ class BytecodeCompiler(
updateSlotType(loopSlotId, SlotType.INT)
updateSlotTypeByName(stmt.loopVarName, SlotType.INT)
loopStack.addLast(
LoopContext(stmt.label, endLabel, continueLabel, breakFlagSlot, if (wantResult) resultSlot else null)
LoopContext(
stmt.label,
endLabel,
continueLabel,
breakFlagSlot,
if (wantResult) resultSlot else null,
hasIterator = false
)
)
val bodyValue = compileLoopBody(stmt.body, wantResult) ?: return null
loopStack.removeLast()
@ -2429,7 +2462,14 @@ class BytecodeCompiler(
listOf(CmdBuilder.Operand.IntVal(condition.slot), CmdBuilder.Operand.LabelRef(endLabel))
)
loopStack.addLast(
LoopContext(stmt.label, endLabel, continueLabel, breakFlagSlot, if (wantResult) resultSlot else null)
LoopContext(
stmt.label,
endLabel,
continueLabel,
breakFlagSlot,
if (wantResult) resultSlot else null,
hasIterator = false
)
)
val bodyValue = compileLoopBody(stmt.body, wantResult) ?: return null
loopStack.removeLast()
@ -2471,7 +2511,14 @@ class BytecodeCompiler(
val endLabel = builder.label()
builder.mark(loopLabel)
loopStack.addLast(
LoopContext(stmt.label, endLabel, continueLabel, breakFlagSlot, if (wantResult) resultSlot else null)
LoopContext(
stmt.label,
endLabel,
continueLabel,
breakFlagSlot,
if (wantResult) resultSlot else null,
hasIterator = false
)
)
val bodyValue = compileStatementValueOrFallback(stmt.body, wantResult) ?: return null
loopStack.removeLast()
@ -2577,17 +2624,28 @@ class BytecodeCompiler(
}
}
private fun findLoopContext(label: String?): LoopContext? {
private fun findLoopContextIndex(label: String?): Int? {
if (loopStack.isEmpty()) return null
if (label == null) return loopStack.last()
for (ctx in loopStack.reversed()) {
if (ctx.label == label) return ctx
val stack = loopStack.toList()
if (label == null) return stack.lastIndex
for (i in stack.indices.reversed()) {
if (stack[i].label == label) return i
}
return null
}
private fun emitIteratorCancel(stack: List<LoopContext>, startIndex: Int) {
for (i in stack.lastIndex downTo startIndex) {
if (stack[i].hasIterator) {
builder.emit(Opcode.ITER_CANCEL)
}
}
}
private fun compileBreak(stmt: net.sergeych.lyng.BreakStatement): CompiledValue? {
val ctx = findLoopContext(stmt.label) ?: return null
val stack = loopStack.toList()
val targetIndex = findLoopContextIndex(stmt.label) ?: return null
val ctx = stack[targetIndex]
val value = stmt.resultExpr?.let { compileStatementValueOrFallback(it) }
if (ctx.resultSlot != null) {
val objValue = value?.let { ensureObjSlot(it) } ?: run {
@ -2601,6 +2659,7 @@ class BytecodeCompiler(
} else if (value != null) {
ensureObjSlot(value)
}
emitIteratorCancel(stack, targetIndex)
val trueId = builder.addConst(BytecodeConst.Bool(true))
builder.emit(Opcode.CONST_BOOL, trueId, ctx.breakFlagSlot)
builder.emit(Opcode.JMP, listOf(CmdBuilder.Operand.LabelRef(ctx.breakLabel)))
@ -2608,7 +2667,12 @@ class BytecodeCompiler(
}
private fun compileContinue(stmt: net.sergeych.lyng.ContinueStatement): CompiledValue? {
val ctx = findLoopContext(stmt.label) ?: return null
val stack = loopStack.toList()
val targetIndex = findLoopContextIndex(stmt.label) ?: return null
val ctx = stack[targetIndex]
if (targetIndex < stack.lastIndex) {
emitIteratorCancel(stack, targetIndex + 1)
}
builder.emit(Opcode.JMP, listOf(CmdBuilder.Operand.LabelRef(ctx.continueLabel)))
return CompiledValue(ctx.breakFlagSlot, SlotType.BOOL)
}

14
lynglib/src/commonMain/kotlin/net/sergeych/lyng/bytecode/BytecodeStatement.kt
View File

@ -19,6 +19,7 @@ package net.sergeych.lyng.bytecode
import net.sergeych.lyng.Pos
import net.sergeych.lyng.Scope
import net.sergeych.lyng.Statement
import net.sergeych.lyng.DestructuringVarDeclStatement
import net.sergeych.lyng.WhenCase
import net.sergeych.lyng.WhenCondition
import net.sergeych.lyng.WhenEqualsCondition
@ -100,6 +101,8 @@ class BytecodeStatement private constructor(
target.statements().any { containsUnsupportedStatement(it) }
is net.sergeych.lyng.VarDeclStatement ->
target.initializer?.let { containsUnsupportedStatement(it) } ?: false
is net.sergeych.lyng.DestructuringVarDeclStatement ->
containsUnsupportedStatement(target.initializer)
is net.sergeych.lyng.BreakStatement ->
target.resultExpr?.let { containsUnsupportedStatement(it) } ?: false
is net.sergeych.lyng.ContinueStatement -> false
@ -147,6 +150,17 @@ class BytecodeStatement private constructor(
stmt.pos
)
}
is net.sergeych.lyng.DestructuringVarDeclStatement -> {
net.sergeych.lyng.DestructuringVarDeclStatement(
stmt.pattern,
stmt.names,
unwrapDeep(stmt.initializer),
stmt.isMutable,
stmt.visibility,
stmt.isTransient,
stmt.pos
)
}
is net.sergeych.lyng.IfStatement -> {
net.sergeych.lyng.IfStatement(
unwrapDeep(stmt.condition),

7
lynglib/src/commonMain/kotlin/net/sergeych/lyng/bytecode/CmdBuilder.kt
View File

@ -192,6 +192,10 @@ class CmdBuilder {
listOf(OperandKind.ID, OperandKind.SLOT)
Opcode.EVAL_FALLBACK, Opcode.EVAL_REF, Opcode.EVAL_STMT, Opcode.EVAL_VALUE_FN ->
listOf(OperandKind.ID, OperandKind.SLOT)
Opcode.ITER_PUSH ->
listOf(OperandKind.SLOT)
Opcode.ITER_POP, Opcode.ITER_CANCEL ->
emptyList()
}
}
@ -387,6 +391,9 @@ class CmdBuilder {
Opcode.EVAL_REF -> CmdEvalRef(operands[0], operands[1])
Opcode.EVAL_STMT -> CmdEvalStmt(operands[0], operands[1])
Opcode.EVAL_VALUE_FN -> CmdEvalValueFn(operands[0], operands[1])
Opcode.ITER_PUSH -> CmdIterPush(operands[0])
Opcode.ITER_POP -> CmdIterPop()
Opcode.ITER_CANCEL -> CmdIterCancel()
}
}
}

8
lynglib/src/commonMain/kotlin/net/sergeych/lyng/bytecode/CmdDisassembler.kt
View File

@ -191,6 +191,9 @@ object CmdDisassembler {
is CmdEvalRef -> Opcode.EVAL_REF to intArrayOf(cmd.id, cmd.dst)
is CmdEvalStmt -> Opcode.EVAL_STMT to intArrayOf(cmd.id, cmd.dst)
is CmdEvalValueFn -> Opcode.EVAL_VALUE_FN to intArrayOf(cmd.id, cmd.dst)
is CmdIterPush -> Opcode.ITER_PUSH to intArrayOf(cmd.iterSlot)
is CmdIterPop -> Opcode.ITER_POP to intArrayOf()
is CmdIterCancel -> Opcode.ITER_CANCEL to intArrayOf()
}
}
@ -205,7 +208,8 @@ object CmdDisassembler {
private fun operandKinds(op: Opcode): List<OperandKind> {
return when (op) {
Opcode.NOP, Opcode.RET_VOID, Opcode.POP_SCOPE, Opcode.POP_SLOT_PLAN -> emptyList()
Opcode.NOP, Opcode.RET_VOID, Opcode.POP_SCOPE, Opcode.POP_SLOT_PLAN,
Opcode.ITER_POP, Opcode.ITER_CANCEL -> emptyList()
Opcode.MOVE_OBJ, Opcode.MOVE_INT, Opcode.MOVE_REAL, Opcode.MOVE_BOOL, Opcode.BOX_OBJ,
Opcode.INT_TO_REAL, Opcode.REAL_TO_INT, Opcode.BOOL_TO_INT, Opcode.INT_TO_BOOL,
Opcode.NEG_INT, Opcode.NEG_REAL, Opcode.NOT_BOOL, Opcode.INV_INT ->
@ -248,7 +252,7 @@ object CmdDisassembler {
Opcode.ADD_OBJ, Opcode.SUB_OBJ, Opcode.MUL_OBJ, Opcode.DIV_OBJ, Opcode.MOD_OBJ, Opcode.CONTAINS_OBJ,
Opcode.AND_BOOL, Opcode.OR_BOOL ->
listOf(OperandKind.SLOT, OperandKind.SLOT, OperandKind.SLOT)
Opcode.INC_INT, Opcode.DEC_INT, Opcode.RET ->
Opcode.INC_INT, Opcode.DEC_INT, Opcode.RET, Opcode.ITER_PUSH ->
listOf(OperandKind.SLOT)
Opcode.JMP ->
listOf(OperandKind.IP)

56
lynglib/src/commonMain/kotlin/net/sergeych/lyng/bytecode/CmdRuntime.kt
View File

@ -32,11 +32,17 @@ class CmdVm {
result = null
val frame = CmdFrame(this, fn, scope0, args)
val cmds = fn.cmds
while (result == null) {
val cmd = cmds[frame.ip]
frame.ip += 1
cmd.perform(frame)
try {
while (result == null) {
val cmd = cmds[frame.ip]
frame.ip += 1
cmd.perform(frame)
}
} catch (e: Throwable) {
frame.cancelIterators()
throw e
}
frame.cancelIterators()
return result ?: ObjVoid
}
}
@ -1419,6 +1425,27 @@ class CmdEvalValueFn(internal val id: Int, internal val dst: Int) : Cmd() {
}
}
class CmdIterPush(internal val iterSlot: Int) : Cmd() {
override suspend fun perform(frame: CmdFrame) {
frame.pushIterator(frame.slotToObj(iterSlot))
return
}
}
class CmdIterPop : Cmd() {
override suspend fun perform(frame: CmdFrame) {
frame.popIterator()
return
}
}
class CmdIterCancel : Cmd() {
override suspend fun perform(frame: CmdFrame) {
frame.cancelTopIterator()
return
}
}
class CmdFrame(
val vm: CmdVm,
val fn: CmdFunction,
@ -1440,6 +1467,7 @@ class CmdFrame(
internal val slotPlanScopeStack = ArrayDeque<Boolean>()
private var scopeDepth = 0
private var virtualDepth = 0
private val iterStack = ArrayDeque<Obj>()
internal val frame = BytecodeFrame(fn.localCount, args.size)
private val addrScopes: Array<Scope?> = arrayOfNulls(fn.addrCount)
@ -1484,6 +1512,26 @@ class CmdFrame(
scopeDepth -= 1
}
fun pushIterator(iter: Obj) {
iterStack.addLast(iter)
}
fun popIterator() {
iterStack.removeLastOrNull()
}
suspend fun cancelTopIterator() {
val iter = iterStack.removeLastOrNull() ?: return
iter.invokeInstanceMethod(scope, "cancelIteration") { ObjVoid }
}
suspend fun cancelIterators() {
while (iterStack.isNotEmpty()) {
val iter = iterStack.removeLast()
iter.invokeInstanceMethod(scope, "cancelIteration") { ObjVoid }
}
}
fun pushSlotPlan(plan: Map<String, Int>) {
if (scope.hasSlotPlanConflict(plan)) {
scopeStack.addLast(scope)

3
lynglib/src/commonMain/kotlin/net/sergeych/lyng/bytecode/Opcode.kt
View File

@ -149,6 +149,9 @@ enum class Opcode(val code: Int) {
EVAL_REF(0xBC),
EVAL_STMT(0xBD),
EVAL_VALUE_FN(0xBE),
ITER_PUSH(0xBF),
ITER_POP(0xC0),
ITER_CANCEL(0xC1),
;
companion object {

3
lynglib/src/commonTest/kotlin/ScriptTest.kt
View File

@ -186,7 +186,6 @@ class ScriptTest {
assertEquals(0, ti.cancelCount)
}
@Ignore("Bytecode: unsupported or incorrect behavior")
@Test
fun testForLoopCancelsOnBreak() = runTest {
val scope = Script.newScope()
@ -202,7 +201,6 @@ class ScriptTest {
assertEquals(1, ti.cancelCount)
}
@Ignore("Bytecode: unsupported or incorrect behavior")
@Test
fun testForLoopCancelsOnException() = runTest {
val scope = Script.newScope()
@ -4567,7 +4565,6 @@ class ScriptTest {
}
@Ignore("Bytecode: unsupported or incorrect behavior")
@Test
fun testDestructuringAssignment() = runTest {
eval(