From 67f0debc923dc97fd79554678435f113c9f761d1 Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Wed, 27 Oct 2021 15:15:04 +0200
Subject: Fix an issue with reading local variables when nested

---
 src/bytecode/compiler.h | 23 ++++++++++++++++-------
 src/bytecode/debug.h    |  5 -----
 src/bytecode/vm.h       |  7 +++++--
 3 files changed, 21 insertions(+), 14 deletions(-)

(limited to 'src')

diff --git a/src/bytecode/compiler.h b/src/bytecode/compiler.h
index f9e1da1..27ff312 100755
--- a/src/bytecode/compiler.h
+++ b/src/bytecode/compiler.h
@@ -608,17 +608,26 @@ parse_tree(Chunk *chunk, Compiler *compiler) {
             return;
         } break;
         case TOKEN_SYMBOL: {
-            Scope *scope = get_current_scope(compiler);
-            ssize_t idx = find_local_index(scope, tok);
-            if (idx < 0) {
+            size_t depth = compiler->scope_depth - 1;
+            ssize_t idx = -1;
+            do {
+                Scope *scope = &compiler->scopes[depth];
+                idx = find_local_index(scope, tok);
+                if (idx >= 0) {
+                    break;
+                }
+                depth--;
+            } while (depth > 0);
+
+            if (idx >= 0) {
+                emit_constant(chunk, tok, FIXNUM_VAL(depth));
+                emit_constant(chunk, tok, FIXNUM_VAL(idx));
+                add_code(chunk, OP_LOCAL, tok.line, tok.column);
+            } else {
                 Object obj = make_symbol(tok.value);
                 emit_constant(chunk, tok, obj);
                 add_code(chunk, OP_GET, tok.line, tok.column);
-                return;
             }
-
-            add_code(chunk, OP_LOCAL, tok.line, tok.column);
-            add_code(chunk, idx, tok.line, tok.column);
             return;
         } break;
         case TOKEN_NIL: {
diff --git a/src/bytecode/debug.h b/src/bytecode/debug.h
index e2e3756..e34b65f 100755
--- a/src/bytecode/debug.h
+++ b/src/bytecode/debug.h
@@ -77,11 +77,6 @@ disassemble_instruction(Chunk *chunk, size_t offset) {
     }
     u8 instruction = chunk->code[offset];
     switch (instruction) {
-        case OP_LOCAL: {
-            u8 local = chunk->code[offset + 1];
-            printf("%-16s %4d\n", ops_str[instruction], local);
-            return offset + 2;
-        } break;
         case OP_CONSTANT: {
             u8 constant = chunk->code[offset + 1];
             printf("%-16s %4d -> ", ops_str[instruction], constant);
diff --git a/src/bytecode/vm.h b/src/bytecode/vm.h
index 15a6b86..3c99131 100755
--- a/src/bytecode/vm.h
+++ b/src/bytecode/vm.h
@@ -175,8 +175,11 @@ vm_interpret(VM *vm) {
         u8 instruction = *vm->pc++;
         switch (instruction) {
             case OP_LOCAL: {
-                u8 local = *vm->pc++;
-                array_push(vm->stack, vm->stack[frame->stack_offset + local]);
+                ssize_t idx = AS_FIXNUM(array_pop(vm->stack));
+                ssize_t depth = AS_FIXNUM(array_pop(vm->stack));
+                CallFrame frame = vm->frames[depth];
+                array_push(vm->stack, vm->stack[frame.stack_offset + idx]);
+
             } break;
             case OP_CONSTANT: {
                 u8 constant = *vm->pc++;
-- 
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