not always

src/compiler/compiler.ts

@@ -334,15 +334,17 @@ export class Compiler {
         if (opValue === '??=') {
           instructions.push(['LOAD', identifierName])
 
+          const skipLabel: Label = `.skip_${this.labelCount++}`
           const rightInstructions = this.#compileNode(right, input)
 
           instructions.push(['DUP'])
           instructions.push(['PUSH', null])
           instructions.push(['NEQ'])
-          instructions.push(['JUMP_IF_TRUE', rightInstructions.length + 1])
+          instructions.push(['JUMP_IF_TRUE', skipLabel])
           instructions.push(['POP'])
           instructions.push(...rightInstructions)
 
+          instructions.push([`${skipLabel}:`])
           instructions.push(['DUP'])
           instructions.push(['STORE', identifierName])
 
@@ -440,8 +442,8 @@ export class Compiler {
       case terms.FunctionCallOrIdentifier: {
         if (node.firstChild?.type.id === terms.DotGet) {
           const instructions: ProgramItem[] = []
-          const callLabel = `.call_dotget_${++this.labelCount}`
+          const callLabel: Label = `.call_dotget_${++this.labelCount}`
-          const afterLabel = `.after_dotget_${++this.labelCount}`
+          const afterLabel: Label = `.after_dotget_${++this.labelCount}`
 
           instructions.push(...this.#compileNode(node.firstChild, input))
           instructions.push(['DUP'])
@@ -603,19 +605,24 @@ export class Compiler {
         instructions.push(...this.#compileNode(conditionNode, input))
         this.ifLabelCount++
         const endLabel: Label = `.end_${this.ifLabelCount}`
+        const elseLabel: Label = `.else_${this.ifLabelCount}`
 
         const thenBlockInstructions = this.#compileNode(thenBlock, input)
-        instructions.push(['JUMP_IF_FALSE', thenBlockInstructions.length + 1])
+        instructions.push(['JUMP_IF_FALSE', elseLabel])
         instructions.push(...thenBlockInstructions)
         instructions.push(['JUMP', endLabel])
 
+        instructions.push([`${elseLabel}:`])
+
         // Else if
-        elseIfBlocks.forEach(({ conditional, thenBlock }) => {
+        elseIfBlocks.forEach(({ conditional, thenBlock }, index) => {
           instructions.push(...this.#compileNode(conditional, input))
+          const nextLabel: Label = `.elsif_${this.ifLabelCount}_${index}`
           const elseIfInstructions = this.#compileNode(thenBlock, input)
-          instructions.push(['JUMP_IF_FALSE', elseIfInstructions.length + 1])
+          instructions.push(['JUMP_IF_FALSE', nextLabel])
           instructions.push(...elseIfInstructions)
           instructions.push(['JUMP', endLabel])
+          instructions.push([`${nextLabel}:`])
         })
 
         // Else
@@ -664,34 +671,41 @@ export class Compiler {
             instructions.push(...leftInstructions, ...rightInstructions, ['GTE'])
             break
 
-          case 'and':
+          case 'and': {
+            const skipLabel: Label = `.skip_${this.labelCount++}`
             instructions.push(...leftInstructions)
             instructions.push(['DUP'])
-            instructions.push(['JUMP_IF_FALSE', rightInstructions.length + 1])
+            instructions.push(['JUMP_IF_FALSE', skipLabel])
             instructions.push(['POP'])
             instructions.push(...rightInstructions)
+            instructions.push([`${skipLabel}:`])
             break
+          }
 
-          case 'or':
+          case 'or': {
+            const skipLabel: Label = `.skip_${this.labelCount++}`
             instructions.push(...leftInstructions)
             instructions.push(['DUP'])
-            instructions.push(['JUMP_IF_TRUE', rightInstructions.length + 1])
+            instructions.push(['JUMP_IF_TRUE', skipLabel])
             instructions.push(['POP'])
             instructions.push(...rightInstructions)
-
+            instructions.push([`${skipLabel}:`])
             break
+          }
 
-          case '??':
+          case '??': {
             // Nullish coalescing: return left if not null, else right
+            const skipLabel: Label = `.skip_${this.labelCount++}`
             instructions.push(...leftInstructions)
             instructions.push(['DUP'])
             instructions.push(['PUSH', null])
             instructions.push(['NEQ'])
-            instructions.push(['JUMP_IF_TRUE', rightInstructions.length + 1])
+            instructions.push(['JUMP_IF_TRUE', skipLabel])
             instructions.push(['POP'])
             instructions.push(...rightInstructions)
-
+            instructions.push([`${skipLabel}:`])
             break
+          }
 
           default:
             throw new CompilerError(`Unsupported conditional operator: ${opValue}`, op.from, op.to)

src/compiler/tests/compiler.test.ts

@@ -188,6 +188,16 @@ describe('compiler', () => {
   test('single line if', () => {
     expect(`if 3 < 9: shire end`).toEvaluateTo('shire')
   })
+
+  test('if statement with function definition (bytecode labels)', () => {
+    expect(`
+      if false:
+        abc = do x: x end
+      else:
+        nope
+      end
+      `).toEvaluateTo('nope')
+  })
 })
 
 describe('errors', () => {