language: implement proper virtual machine support

bir/src/main/kotlin/gay/pizza/pork/bir/IrBreak.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrBreak(val target: IrSymbol) : IrCodeElement {
   override fun crawl(block: (IrElement) -> Unit) {
     block(target)

bir/src/main/kotlin/gay/pizza/pork/bir/IrCall.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrCall(
   override val target: IrSymbol,
   val arguments: List<IrCodeElement>,

bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeBlock.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrCodeBlock(val items: List<IrCodeElement>) : IrCodeElement {
   override fun crawl(block: (IrElement) -> Unit) {
     items.forEach(block)

bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeElement.kt

@@ -1,3 +1,6 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 sealed interface IrCodeElement : IrElement

bir/src/main/kotlin/gay/pizza/pork/bir/IrCodeVisitor.kt

@@ -1,6 +1,4 @@
-package gay.pizza.pork.compiler
-
-import gay.pizza.pork.bir.*
+package gay.pizza.pork.bir
 
 interface IrCodeVisitor<T> : IrVisitor<T> {
   override fun visitIrDefinition(ir: IrDefinition): T {

bir/src/main/kotlin/gay/pizza/pork/bir/IrConditional.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrConditional(
   val conditional: IrCodeElement,
   val ifTrue: IrCodeElement,

bir/src/main/kotlin/gay/pizza/pork/bir/IrConstant.kt

@@ -1,12 +1,26 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 sealed interface IrConstant : IrCodeElement {
   override fun crawl(block: (IrElement) -> Unit) {}
 }
 
+@Serializable
 data class IrIntegerConstant(val value: Int) : IrConstant
+
+@Serializable
 data class IrLongConstant(val value: Long) : IrConstant
+
+@Serializable
 data class IrDoubleConstant(val value: Double) : IrConstant
+
+@Serializable
 data class IrStringConstant(val value: String) : IrConstant
+
+@Serializable
 data class IrBooleanConstant(val value: Boolean) : IrConstant
+
+@Serializable
 data object IrNoneConstant : IrConstant

bir/src/main/kotlin/gay/pizza/pork/bir/IrContinue.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrContinue(override val target: IrSymbol) : IrCodeElement, IrSymbolUser {
   override fun crawl(block: (IrElement) -> Unit) {
     block(target)

bir/src/main/kotlin/gay/pizza/pork/bir/IrDefinition.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrDefinition(
   override val symbol: IrSymbol,
   val type: IrDefinitionType,

bir/src/main/kotlin/gay/pizza/pork/bir/IrDefinitionType.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 enum class IrDefinitionType {
   Variable,
   CodeFunction,

bir/src/main/kotlin/gay/pizza/pork/bir/IrElement.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 sealed interface IrElement {
   fun crawl(block: (IrElement) -> Unit)
 }

bir/src/main/kotlin/gay/pizza/pork/bir/IrFunctionArgument.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrFunctionArgument(override val symbol: IrSymbol) : IrSymbolOwner {
   override fun crawl(block: (IrElement) -> Unit) {}
 }

bir/src/main/kotlin/gay/pizza/pork/bir/IrIndex.kt

@@ -0,0 +1,11 @@
+package gay.pizza.pork.bir
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class IrIndex(val data: IrCodeElement, val index: IrCodeElement) : IrCodeElement {
+  override fun crawl(block: (IrElement) -> Unit) {
+    block(data)
+    block(index)
+  }
+}

bir/src/main/kotlin/gay/pizza/pork/bir/IrInfix.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrInfix(val op: IrInfixOp, val left: IrCodeElement, val right: IrCodeElement) : IrCodeElement {
   override fun crawl(block: (IrElement) -> Unit) {
     block(left)

bir/src/main/kotlin/gay/pizza/pork/bir/IrInfixOp.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 enum class IrInfixOp {
   Add,
   Subtract,

bir/src/main/kotlin/gay/pizza/pork/bir/IrList.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrList(val items: List<IrCodeElement>) : IrCodeElement {
   override fun crawl(block: (IrElement) -> Unit) {
     items.forEach(block)

bir/src/main/kotlin/gay/pizza/pork/bir/IrListSize.kt

@@ -0,0 +1,10 @@
+package gay.pizza.pork.bir
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class IrListSize(val list: IrCodeElement) : IrCodeElement {
+  override fun crawl(block: (IrElement) -> Unit) {
+    block(list)
+  }
+}

bir/src/main/kotlin/gay/pizza/pork/bir/IrLoad.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrLoad(override val target: IrSymbol) : IrCodeElement, IrSymbolUser {
   override fun crawl(block: (IrElement) -> Unit) {
     block(target)

bir/src/main/kotlin/gay/pizza/pork/bir/IrLoop.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrLoop(
   override val symbol: IrSymbol,
   val condition: IrCodeElement,

bir/src/main/kotlin/gay/pizza/pork/bir/IrNativeDefinition.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrNativeDefinition(val form: String, val definitions: List<String>) : IrCodeElement {
   override fun crawl(block: (IrElement) -> Unit) {}
 }

bir/src/main/kotlin/gay/pizza/pork/bir/IrPrefix.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrPrefix(val op: IrPrefixOp, val value: IrCodeElement) : IrCodeElement {
   override fun crawl(block: (IrElement) -> Unit) {
     block(value)

bir/src/main/kotlin/gay/pizza/pork/bir/IrPrefixOp.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 enum class IrPrefixOp {
   BooleanNot,
   UnaryPlus,

bir/src/main/kotlin/gay/pizza/pork/bir/IrReturn.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrReturn(val from: IrSymbol, val value: IrCodeElement) : IrCodeElement {
   override fun crawl(block: (IrElement) -> Unit) {
     block(from)

bir/src/main/kotlin/gay/pizza/pork/bir/IrSlab.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrSlab(
   val location: IrSlabLocation,
   val definitions: List<IrDefinition>

bir/src/main/kotlin/gay/pizza/pork/bir/IrSlabLocation.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrSlabLocation(
   val form: String,
   val path: String

bir/src/main/kotlin/gay/pizza/pork/bir/IrStore.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrStore(override val target: IrSymbol, val value: IrCodeElement) : IrCodeElement, IrSymbolUser {
   override fun crawl(block: (IrElement) -> Unit) {
     value.crawl(block)

bir/src/main/kotlin/gay/pizza/pork/bir/IrSuffix.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrSuffix(val op: IrSuffixOp, override val target: IrSymbol) : IrCodeElement, IrSymbolUser {
   override fun crawl(block: (IrElement) -> Unit) {
     block(target)

bir/src/main/kotlin/gay/pizza/pork/bir/IrSuffixOp.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 enum class IrSuffixOp {
   Increment,
   Decrement

bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbol.kt

@@ -1,5 +1,24 @@
 package gay.pizza.pork.bir
 
-data class IrSymbol(val id: UInt, val tag: IrSymbolTag) : IrElement {
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class IrSymbol(val id: UInt, val tag: IrSymbolTag, val name: String? = null) : IrElement {
   override fun crawl(block: (IrElement) -> Unit) {}
+
+  override fun equals(other: Any?): Boolean {
+    if (other !is IrSymbol) return false
+    return other.id == id && other.tag == tag
+  }
+
+  override fun hashCode(): Int {
+    var result = id.hashCode()
+    result = 31 * result + tag.hashCode()
+    return result
+  }
+
+  val friendlyName: String
+    get() = if (name != null) {
+      "$id $tag $name"
+    } else "$id $tag"
 }

bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolAssignment.kt

@@ -4,5 +4,6 @@ class IrSymbolAssignment {
   private var index = 0u
 
   private fun nextSymbolId(): UInt = index++
-  fun next(tag: IrSymbolTag): IrSymbol = IrSymbol(nextSymbolId(), tag)
+  fun next(tag: IrSymbolTag, name: String? = null): IrSymbol =
+    IrSymbol(id = nextSymbolId(), tag = tag, name = name)
 }

bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolOwner.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 sealed interface IrSymbolOwner : IrElement {
   val symbol: IrSymbol
 }

bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolTag.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 enum class IrSymbolTag {
   Function,
   Variable,

bir/src/main/kotlin/gay/pizza/pork/bir/IrSymbolUser.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 sealed interface IrSymbolUser : IrElement {
   val target: IrSymbol
 }

bir/src/main/kotlin/gay/pizza/pork/bir/IrVisitor.kt

@@ -27,6 +27,8 @@ interface IrVisitor<T> {
   fun visitIrWorld(ir: IrWorld): T
   fun visitIrNativeDefinition(ir: IrNativeDefinition): T
   fun visitIrFunctionArgument(ir: IrFunctionArgument): T
+  fun visitIrIndex(ir: IrIndex): T
+  fun visitIrListSize(ir: IrListSize): T
 
   fun visit(ir: IrElement): T = when (ir) {
     is IrBreak -> visitIrBeak(ir)
@@ -55,5 +57,7 @@ interface IrVisitor<T> {
     is IrWorld -> visitIrWorld(ir)
     is IrNativeDefinition -> visitIrNativeDefinition(ir)
     is IrFunctionArgument -> visitIrFunctionArgument(ir)
+    is IrIndex -> visitIrIndex(ir)
+    is IrListSize -> visitIrListSize(ir)
   }
 }

bir/src/main/kotlin/gay/pizza/pork/bir/IrWorld.kt

@@ -1,5 +1,8 @@
 package gay.pizza.pork.bir
 
+import kotlinx.serialization.Serializable
+
+@Serializable
 data class IrWorld(val slabs: List<IrSlab>) : IrElement {
   override fun crawl(block: (IrElement) -> Unit) {
     slabs.forEach(block)

bytecode/src/main/kotlin/gay/pizza/pork/bytecode/Opcode.kt

@@ -33,13 +33,14 @@ enum class Opcode(val id: UByte) {
   ListMake(31u),
   ListSize(32u),
   Integer(33u),
-  Double(34u),
-  Call(35u),
-  EuclideanModulo(36u),
-  Remainder(37u),
-  Index(38u),
-  ScopeIn(39u),
-  ScopeOut(40u),
-  ReturnAddress(41u),
+  Long(34u),
+  Double(35u),
+  Call(36u),
+  EuclideanModulo(37u),
+  Remainder(38u),
+  Index(39u),
+  ScopeIn(40u),
+  ScopeOut(41u),
+  ReturnAddress(42u),
   End(255u),
 }

compiler/src/main/kotlin/gay/pizza/pork/compiler/CompilableSlab.kt

@@ -19,11 +19,6 @@ class CompilableSlab(val compiler: Compiler, val slab: Slab) {
     it.scopeSymbol.symbol == symbol
   }
 
-  fun resolveVisible(symbol: Symbol): CompilableSymbol? {
-    val scopeSymbol = slab.scope.resolve(symbol) ?: return null
-    return compiler.resolveOrNull(scopeSymbol)
-  }
-
   private fun compileIrSlab(): IrSlab {
     val definitions = mutableListOf<IrDefinition>()
     for (compilableSymbol in compilableSymbols) {

compiler/src/main/kotlin/gay/pizza/pork/compiler/CompilableSymbol.kt

@@ -28,7 +28,7 @@ class CompilableSymbol(val compilableSlab: CompilableSlab, val scopeSymbol: Scop
 
   private fun compileIrDefinition(): IrDefinition {
     val compiler = compilableSlab.compiler
-    val functionSymbol = compiler.irSymbolWorld.create(scopeSymbol, IrSymbolTag.Function)
+    val functionSymbol = compiler.irSymbolWorld.create(scopeSymbol, IrSymbolTag.Function, scopeSymbol.symbol.id)
     val irCodeEmitter = IrCodeEmitter(
       self = functionSymbol,
       irSymbolWorld = compiler.irSymbolWorld,

compiler/src/main/kotlin/gay/pizza/pork/compiler/CompiledWorldLayout.kt

@@ -13,7 +13,7 @@ class CompiledWorldLayout(val compiler: Compiler) : StubResolutionContext {
     val stubOps = result.ops
     symbolTable[symbol] = SymbolInfo(
       slab = symbol.compilableSlab.slab.location.commonLocationIdentity,
-      symbol = symbol.id,
+      symbol = symbol.scopeSymbol.symbol.id,
       offset = start.toUInt(),
       size = stubOps.size.toUInt()
     )

compiler/src/main/kotlin/gay/pizza/pork/compiler/Compiler.kt

@@ -1,12 +1,15 @@
 package gay.pizza.pork.compiler
 
+import gay.pizza.pork.bir.IrSlab
 import gay.pizza.pork.bir.IrSymbolAssignment
+import gay.pizza.pork.bir.IrWorld
 import gay.pizza.pork.bytecode.CompiledWorld
 import gay.pizza.pork.bytecode.MutableConstantPool
 import gay.pizza.pork.frontend.Slab
+import gay.pizza.pork.frontend.World
 import gay.pizza.pork.frontend.scope.ScopeSymbol
 
-class Compiler {
+class Compiler(val world: World) {
   val constantPool: MutableConstantPool = MutableConstantPool()
   val compilableSlabs: ComputableState<Slab, CompilableSlab> = ComputableState { slab ->
     CompilableSlab(this, slab)
@@ -39,6 +42,14 @@ class Compiler {
     }
   }
 
+  fun compileIrWorld(): IrWorld {
+    val slabs = mutableListOf<IrSlab>()
+    for (slab in world.slabs) {
+      slabs.add(compilableSlabs.of(slab).compiledIrSlab)
+    }
+    return IrWorld(slabs)
+  }
+
   fun compile(entryPointSymbol: CompilableSymbol): CompiledWorld {
     val usedSymbolSet = mutableSetOf<CompilableSymbol>()
     contributeCompiledSymbols(usedSymbolSet, entryPointSymbol.scopeSymbol, entryPointSymbol)

compiler/src/main/kotlin/gay/pizza/pork/compiler/IrCodeEmitter.kt

@@ -13,7 +13,7 @@ class IrCodeEmitter(
   val scope: SlabScope
 ) : FunctionLevelVisitor<IrCodeElement>() {
   private val loopSymbols = mutableListOf<IrSymbol>()
-  private val localVariables = mutableListOf<MutableMap<String, LocalVariable>>()
+  private val localVariables = mutableListOf<MutableMap<Pair<String?, UInt?>, LocalVariable>>()
 
   var functionArguments: List<IrFunctionArgument> = emptyList()
 
@@ -46,7 +46,7 @@ class IrCodeEmitter(
   }
 
   fun enterLocalScope() {
-    val locals = mutableMapOf<String, LocalVariable>()
+    val locals = mutableMapOf<Pair<String?, UInt?>, LocalVariable>()
     localVariables.add(locals)
   }
 
@@ -54,15 +54,16 @@ class IrCodeEmitter(
     localVariables.removeLast()
   }
 
-  private fun createLocalVariable(name: Symbol): IrSymbol {
-    val symbol = irSymbolAssignment.next(IrSymbolTag.Local)
+  private fun createLocalVariable(name: Symbol? = null): IrSymbol {
+    val symbol = irSymbolAssignment.next(tag = IrSymbolTag.Local, name = name?.id)
     val variable = LocalVariable(symbol, name)
     val variables = localVariables.last()
-    val existing = variables[name.id]
+    val identifier = name?.id to (if (name == null) symbol.id else null)
+    val existing = variables[identifier]
     if (existing != null) {
-      throw CompileError("Unable to define local variable '${name.id}' within this scope, it already exists", name)
+      throw CompileError("Unable to define local variable '${identifier.first}' within this scope, it already exists", name)
     }
-    variables[name.id] = variable
+    variables[identifier] = variable
     return symbol
   }
 
@@ -74,10 +75,11 @@ class IrCodeEmitter(
     }
 
   private fun lookupLocalVariable(name: Symbol): IrSymbol? {
+    val identifier = name.id to null
     for (i in 1..localVariables.size) {
       val b = localVariables.size - i
       val scope = localVariables[b]
-      val found = scope[name.id]
+      val found = scope[identifier]
       if (found != null) {
         return found.symbol
       }
@@ -99,7 +101,7 @@ class IrCodeEmitter(
 
   private fun lookupFunction(name: Symbol): Pair<ScopeSymbol, IrSymbol>? {
     val scoped = scope.resolve(name) ?: return null
-    return scoped to irSymbolWorld.create(scoped, scopeSymbolToTag(scoped))
+    return scoped to irSymbolWorld.create(value = scoped, tag = scopeSymbolToTag(scoped), name = scoped.symbol.id)
   }
 
   override fun visitBlock(node: Block): IrCodeBlock {
@@ -128,7 +130,33 @@ class IrCodeEmitter(
     IrDoubleConstant(node.value)
 
   override fun visitForIn(node: ForIn): IrCodeElement {
-    return IrNoneConstant
+    val listLocal = createLocalVariable()
+    val indexLocal = createLocalVariable()
+    val sizeLocal = createLocalVariable()
+    val loopSymbol = irSymbolAssignment.next(IrSymbolTag.Loop)
+
+    val items = mutableListOf<IrCodeElement>(
+      IrStore(listLocal, visit(node.expression)),
+      IrStore(indexLocal, IrIntegerConstant(0)),
+      IrStore(sizeLocal, IrListSize(IrLoad(listLocal)))
+    )
+
+    enterLocalScope()
+    val loopValueLocal = createLocalVariable(node.item.symbol)
+    val subCodeBlock = visitBlock(node.block)
+    val innerCodeBlock = IrCodeBlock(listOf(
+      IrStore(loopValueLocal, IrIndex(IrLoad(listLocal), IrLoad(indexLocal))),
+      IrStore(indexLocal, IrInfix(IrInfixOp.Add, IrLoad(indexLocal), IrIntegerConstant(1))),
+      subCodeBlock
+    ))
+    exitLocalScope()
+    val loop = IrLoop(
+      symbol = loopSymbol,
+      condition = IrInfix(IrInfixOp.Lesser, IrLoad(indexLocal), IrLoad(sizeLocal)),
+      inner = innerCodeBlock
+    )
+    items.add(loop)
+    return IrCodeBlock(items)
   }
 
   override fun visitFunctionCall(node: FunctionCall): IrCodeElement {
@@ -169,19 +197,20 @@ class IrCodeEmitter(
       variableArguments = mutableListOf()
     }
 
-    return IrCall(symbol, arguments, variableArguments)
+    return IrCall(target = symbol, arguments = arguments, variableArguments = variableArguments)
   }
 
   override fun visitIf(node: If): IrCodeElement =
     IrConditional(
-      node.condition.visit(this),
-      node.thenBlock.visit(this),
-      node.elseBlock?.visit(this) ?: IrNoneConstant
+      conditional = node.condition.visit(this),
+      ifTrue = node.thenBlock.visit(this),
+      ifFalse = node.elseBlock?.visit(this) ?: IrNoneConstant
     )
 
-  override fun visitIndexedBy(node: IndexedBy): IrCodeElement {
-    TODO("Not yet implemented")
-  }
+  override fun visitIndexedBy(node: IndexedBy): IrCodeElement = IrIndex(
+    data = visit(node.expression),
+    index = visit(node.index)
+  )
 
   override fun visitInfixOperation(node: InfixOperation): IrCodeElement {
     val op = when (node.op) {

compiler/src/main/kotlin/gay/pizza/pork/compiler/IrStubOpEmitter.kt

@@ -74,10 +74,10 @@ class IrStubOpEmitter(val irDefinition: IrDefinition, val code: CodeBuilder) : I
     val endRel = MutableRel(0u)
     visit(ir.conditional)
     code.patch(Opcode.JumpIf, listOf(0u), 0, symbol, thenRel)
-    visit(ir.ifTrue)
+    visit(ir.ifFalse)
     code.patch(Opcode.Jump, listOf(0u), 0, symbol, endRel)
     thenRel.rel = code.nextOpInst()
-    visit(ir.ifFalse)
+    visit(ir.ifTrue)
     endRel.rel = code.nextOpInst()
   }
 
@@ -90,11 +90,16 @@ class IrStubOpEmitter(val irDefinition: IrDefinition, val code: CodeBuilder) : I
   }
 
   override fun visitIrLongConstant(ir: IrLongConstant) {
-    code.emit(Opcode.Integer, listOf(ir.value.toUInt()))
+    val value1 = ir.value.toUInt()
+    val value2 = (ir.value shr 32).toUInt()
+    code.emit(Opcode.Long, listOf(value1, value2))
   }
 
   override fun visitIrDoubleConstant(ir: IrDoubleConstant) {
-    code.emit(Opcode.Integer, listOf(ir.value.toUInt()))
+    val value = ir.value.toRawBits()
+    val value1 = value.toUInt()
+    val value2 = (value shr 32).toUInt()
+    code.emit(Opcode.Double, listOf(value1, value2))
   }
 
   override fun visitIrStringConstant(ir: IrStringConstant) {
@@ -219,4 +224,15 @@ class IrStubOpEmitter(val irDefinition: IrDefinition, val code: CodeBuilder) : I
     )
     code.emit(Opcode.Native, listOf(formConstant, ir.definitions.size.toUInt(), functionArgumentCount.toUInt()))
   }
+
+  override fun visitIrIndex(ir: IrIndex) {
+    visit(ir.index)
+    visit(ir.data)
+    code.emit(Opcode.Index)
+  }
+
+  override fun visitIrListSize(ir: IrListSize) {
+    visit(ir.list)
+    code.emit(Opcode.ListSize)
+  }
 }

compiler/src/main/kotlin/gay/pizza/pork/compiler/IrSymbolWorld.kt

@@ -7,8 +7,8 @@ import gay.pizza.pork.bir.IrSymbolTag
 class IrSymbolWorld<T>(val irSymbolAssignment: IrSymbolAssignment) {
   private val symbols = mutableMapOf<T, IrSymbol>()
 
-  fun create(value: T, tag: IrSymbolTag): IrSymbol = symbols.getOrPut(value) {
-    irSymbolAssignment.next(tag)
+  fun create(value: T, tag: IrSymbolTag, name: String? = null): IrSymbol = symbols.getOrPut(value) {
+    irSymbolAssignment.next(tag, name)
   }
 
   fun resolve(value: T): IrSymbol? = symbols[value]

compiler/src/main/kotlin/gay/pizza/pork/compiler/LocalVariable.kt

@@ -3,4 +3,4 @@ package gay.pizza.pork.compiler
 import gay.pizza.pork.ast.gen.Symbol
 import gay.pizza.pork.bir.IrSymbol
 
-data class LocalVariable(val symbol: IrSymbol, val name: Symbol)
+data class LocalVariable(val symbol: IrSymbol, val name: Symbol? = null)

examples/fib.pork

@@ -1,9 +1,9 @@
 /* fibonacci sequence */
 func fib(n) {
-  return if n < 2 {
-    n
+  if n < 2 {
+    return n
   } else {
-    fib(n - 1) + fib(n - 2)
+    return fib(n - 1) + fib(n - 2)
   }
 }
 

examples/for.pork

@@ -1,6 +1,5 @@
-let items = ["Hello", "Goodbye"]
-
 export func main() {
+  let items = ["Hello", "Goodbye"]
   for item in items {
     println(item)
   }

examples/list.pork

@@ -0,0 +1,6 @@
+export func main() {
+  let items = listInitWith(30, 0)
+  for item in items {
+    println(item)
+  }
+}

execution/src/main/kotlin/gay/pizza/pork/execution/NativeRegistry.kt

@@ -14,5 +14,5 @@ class NativeRegistry {
   }
 
   fun of(form: String): NativeProvider =
-    providers[form] ?: throw RuntimeException("Unknown native form: ${form}")
+    providers[form] ?: throw RuntimeException("Unknown native form: $form")
 }

tool/src/main/kotlin/gay/pizza/pork/tool/CompileCommand.kt

@@ -4,21 +4,40 @@ import com.github.ajalt.clikt.core.CliktCommand
 import com.github.ajalt.clikt.parameters.arguments.argument
 import gay.pizza.dough.fs.PlatformFsProvider
 import gay.pizza.pork.ast.gen.Symbol
+import gay.pizza.pork.bir.IrWorld
+import gay.pizza.pork.bytecode.CompiledWorld
 import gay.pizza.pork.compiler.Compiler
 import gay.pizza.pork.minimal.FileTool
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.json.Json
 
+@OptIn(ExperimentalSerializationApi::class)
 class CompileCommand : CliktCommand(help = "Compile Pork to Bytecode", name = "compile") {
   val path by argument("file")
 
   override fun run() {
     val tool = FileTool(PlatformFsProvider.resolve(path))
     val world = tool.buildWorld()
-    val compiler = Compiler()
+    val compiler = Compiler(world)
     val slab = world.load(tool.rootImportLocator)
     val compiledSlab = compiler.compilableSlabs.of(slab)
     val compiledMain = compiledSlab.resolve(Symbol("main"))
       ?: throw RuntimeException("'main' function not found.")
     val compiledWorld = compiler.compile(compiledMain)
+    val irWorld = compiler.compileIrWorld()
+    printCompiledIr(irWorld)
+    printCompiledWorld(compiledWorld)
+  }
+
+  private fun printCompiledIr(irWorld: IrWorld) {
+    val json = Json {
+      prettyPrint = true
+      prettyPrintIndent = "  "
+    }
+    println(json.encodeToString(IrWorld.serializer(), irWorld))
+  }
+
+  private fun printCompiledWorld(compiledWorld: CompiledWorld) {
     for (symbol in compiledWorld.symbolTable.symbols) {
       val code = compiledWorld.code.subList(symbol.offset.toInt(), (symbol.offset + symbol.size).toInt())
       println(symbol.commonSymbolIdentity)

vm/src/main/kotlin/gay/pizza/pork/vm/InternalMachine.kt

@@ -47,11 +47,14 @@ class InternalMachine(val world: CompiledWorld, val nativeRegistry: NativeRegist
     }
   }
 
-  fun loadLocal(id: UInt) {
+  fun localAt(id: UInt): Any {
     val localSet = locals.last()
-    val local = localSet[id]
-      ?: throw VirtualMachineException("Attempted to load local $id but it was not stored.")
-    push(local)
+    return localSet[id] ?:
+      throw VirtualMachineException("Attempted to load local $id but it was not stored.")
+  }
+
+  fun loadLocal(id: UInt) {
+    push(localAt(id))
   }
 
   fun storeLocal(id: UInt) {
@@ -108,4 +111,11 @@ class InternalMachine(val world: CompiledWorld, val nativeRegistry: NativeRegist
     exitFlag = false
     autoNextInst = true
   }
+
+  fun frame(at: UInt = inst): StackFrame? {
+    val (symbolInfo, rel) = world.symbolTable.lookup(at) ?: (null to null)
+    return if (symbolInfo != null && rel != null) {
+      StackFrame(symbolInfo, rel)
+    } else null
+  }
 }

vm/src/main/kotlin/gay/pizza/pork/vm/StackFrame.kt

@@ -0,0 +1,19 @@
+package gay.pizza.pork.vm
+
+import gay.pizza.pork.bytecode.CompiledWorld
+import gay.pizza.pork.bytecode.Op
+import gay.pizza.pork.bytecode.SymbolInfo
+
+data class StackFrame(val symbolInfo: SymbolInfo, val rel: UInt) {
+  val worldCodeOffset: UInt
+    get() = symbolInfo.offset + rel
+
+  fun opInWorld(world: CompiledWorld): Op =
+    world.code[worldCodeOffset.toInt()]
+
+  fun describeInWorld(world: CompiledWorld): String =
+    "StackFrame(${worldCodeOffset}, ${symbolInfo.slab} ${symbolInfo.symbol} + ${rel}, ${opInWorld(world)})"
+
+  override fun toString(): String =
+    "StackFrame(${worldCodeOffset}, ${symbolInfo.slab} ${symbolInfo.symbol} + ${rel})"
+}

vm/src/main/kotlin/gay/pizza/pork/vm/VirtualMachineProvider.kt

@@ -10,7 +10,7 @@ import gay.pizza.pork.frontend.World
 
 class VirtualMachineProvider(val world: World) : ExecutionContextProvider {
   override fun prepare(importLocator: ImportLocator, entryPointSymbol: Symbol, nativeRegistry: NativeRegistry): ExecutionContext {
-    val compiler = Compiler()
+    val compiler = Compiler(world)
     val slab = world.load(importLocator)
     val compilableSlab = compiler.compilableSlabs.of(slab)
     val compilableSymbol = compilableSlab.resolve(entryPointSymbol) ?:

vm/src/main/kotlin/gay/pizza/pork/vm/ops/AddOpHandler.kt

@@ -7,8 +7,8 @@ import gay.pizza.pork.vm.OpHandler
 
 object AddOpHandler : OpHandler(Opcode.Add) {
   override fun handle(machine: InternalMachine, op: Op) {
-    val left = machine.pop<Int>()
     val right = machine.pop<Int>()
+    val left = machine.pop<Int>()
     machine.push(left + right)
   }
 }

vm/src/main/kotlin/gay/pizza/pork/vm/ops/NativeOpHandler.kt

@@ -2,6 +2,7 @@ package gay.pizza.pork.vm.ops
 
 import gay.pizza.pork.bytecode.Op
 import gay.pizza.pork.bytecode.Opcode
+import gay.pizza.pork.execution.None
 import gay.pizza.pork.vm.InternalMachine
 import gay.pizza.pork.vm.OpHandler
 
@@ -9,9 +10,10 @@ object NativeOpHandler : OpHandler(Opcode.Native) {
   override fun handle(machine: InternalMachine, op: Op) {
     val argumentCount = op.args[2]
     val arguments = mutableListOf<Any>()
-    for (i in 0u until argumentCount) {
-      machine.loadLocal(i)
-      arguments.add(machine.popAnyValue())
+    var x = argumentCount
+    while (x > 0u) {
+      x--
+      arguments.add(machine.localAt(x))
     }
     val formConstant = machine.world.constantPool.read(op.args[0])
     val form = formConstant.readAsString()
@@ -22,6 +24,7 @@ object NativeOpHandler : OpHandler(Opcode.Native) {
       defs.add(machine.pop())
     }
     val function = provider.provideNativeFunction(defs)
-    function.invoke(arguments)
+    val result = function.invoke(arguments)
+    machine.push(if (result == Unit) None else result)
   }
 }

vm/src/main/kotlin/gay/pizza/pork/vm/ops/SubtractOpHandler.kt

@@ -7,8 +7,8 @@ import gay.pizza.pork.vm.OpHandler
 
 object SubtractOpHandler : OpHandler(Opcode.Subtract) {
   override fun handle(machine: InternalMachine, op: Op) {
-    val left = machine.pop<Int>()
     val right = machine.pop<Int>()
+    val left = machine.pop<Int>()
     machine.push(left - right)
   }
 }