From fcf015508c98d16dd34d87e5df0538b44178143d Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Tue, 26 Oct 2021 15:19:25 +0200
Subject: Checking n_args at runtime for OP_CALL

---
 src/bytecode/vm.h | 47 +++++++++++++++++++++++------------------------
 1 file changed, 23 insertions(+), 24 deletions(-)

(limited to 'src/bytecode/vm.h')

diff --git a/src/bytecode/vm.h b/src/bytecode/vm.h
index 2bc5c8a..ed54046 100755
--- a/src/bytecode/vm.h
+++ b/src/bytecode/vm.h
@@ -60,37 +60,29 @@ vm_reset(VM *vm) {
 }
 
 // Helper macros for a more clear VM switch.
-#define WRONG_ARG_ERR() \
+#define RUNTIME_ERROR(ERR) \
     error_push((Error){ \
         .type = ERR_TYPE_RUNTIME, \
-        .value = ERR_WRONG_ARG_TYPE, \
+        .value = (ERR), \
         .line = frame->chunk->lines[vm->pc - frame->chunk->code - 1].line, \
         .col = frame->chunk->lines[vm->pc - frame->chunk->code - 1].col, \
     }); \
     return
 
-#define SYMBOL_NOT_FOUND_ERR() \
-    error_push((Error){ \
-        .type = ERR_TYPE_RUNTIME, \
-        .value = ERR_SYMBOL_NOT_FOUND, \
-        .line = frame->chunk->lines[vm->pc - frame->chunk->code - 1].line, \
-        .col = frame->chunk->lines[vm->pc - frame->chunk->code - 1].col, \
-    })
-
 #define FIXNUM_ARITHMETIC_OP(OP) \
     do { \
         ssize_t n = AS_FIXNUM(array_pop(vm->stack)); \
         size_t stack_size = array_size(vm->stack) - n; \
         Object obj = array_peek(vm->stack, n - 1); \
         if (!IS_FIXNUM(obj)) { \
-            WRONG_ARG_ERR(); \
+            RUNTIME_ERROR(ERR_WRONG_ARG_TYPE); \
             return; \
         } \
         ssize_t acc = AS_FIXNUM(obj); \
         while (n > 1) { \
             obj = array_peek(vm->stack, n - 2); \
             if (!IS_FIXNUM(obj)) { \
-                WRONG_ARG_ERR(); \
+                RUNTIME_ERROR(ERR_WRONG_ARG_TYPE); \
                 return; \
             } \
             ssize_t current = AS_FIXNUM(obj); \
@@ -107,7 +99,7 @@ vm_reset(VM *vm) {
         size_t stack_size = array_size(vm->stack) - n; \
         Object obj = array_peek(vm->stack, n - 1); \
         if (!IS_FIXNUM(obj)) { \
-            WRONG_ARG_ERR(); \
+            RUNTIME_ERROR(ERR_WRONG_ARG_TYPE); \
             return; \
         } \
         ssize_t prev = AS_FIXNUM(obj); \
@@ -115,7 +107,7 @@ vm_reset(VM *vm) {
         while (n > 1) { \
             obj = array_peek(vm->stack, n - 2); \
             if (!IS_FIXNUM(obj)) { \
-                WRONG_ARG_ERR(); \
+                RUNTIME_ERROR(ERR_WRONG_ARG_TYPE); \
                 return; \
             } \
             ssize_t current = AS_FIXNUM(obj); \
@@ -184,7 +176,7 @@ vm_interpret(VM *vm) {
                 Object name = array_pop(vm->stack);
                 Object *prev = ht_lookup(vm->globals, name);
                 if (prev == NULL) {
-                    SYMBOL_NOT_FOUND_ERR();
+                    RUNTIME_ERROR(ERR_SYMBOL_NOT_FOUND);
                     return;
                 }
                 ht_insert(vm->globals, name, value);
@@ -193,7 +185,7 @@ vm_interpret(VM *vm) {
                 Object name = array_pop(vm->stack);
                 Object *value = ht_lookup(vm->globals, name);
                 if (value == NULL) {
-                    SYMBOL_NOT_FOUND_ERR();
+                    RUNTIME_ERROR(ERR_SYMBOL_NOT_FOUND);
                     return;
                 }
                 array_push(vm->stack, *value);
@@ -235,7 +227,7 @@ vm_interpret(VM *vm) {
             case OP_PRINT: {
                 Object obj = array_pop(vm->stack);
                 if (!IS_STRING(obj)) {
-                    WRONG_ARG_ERR();
+                    RUNTIME_ERROR(ERR_WRONG_ARG_TYPE);
                 }
                 StringView scanner = (StringView) {
                     .start = obj.text,
@@ -260,7 +252,20 @@ vm_interpret(VM *vm) {
                 printf("\n");
             } break;
             case OP_CALL: {
+                ssize_t n_args = AS_FIXNUM(array_pop(vm->stack));
                 Object proc = array_pop(vm->stack);
+
+                // Check the number of arguments is correct.
+                // NOTE: This is probably better handled at compilation, but for
+                // now this is simpler to implement.
+                ssize_t n_params = array_size(proc.chunk->params);
+                if (n_args < n_params) {
+                    RUNTIME_ERROR(ERR_NOT_ENOUGH_ARGS);
+                } else if (n_args > n_params) {
+                    RUNTIME_ERROR(ERR_TOO_MANY_ARGS);
+                }
+
+                // DEBUG:...
                 // disassemble_chunk(proc.chunk);
 
                 // Tail-call optimization.
@@ -299,13 +304,7 @@ vm_interpret(VM *vm) {
                 array_head(vm->stack)->size = 0;
             } break;
             default: {
-                error_push((Error){
-                    .type = ERR_TYPE_RUNTIME,
-                    .value = ERR_NOT_IMPLEMENTED,
-                    .line = frame->chunk->lines[vm->pc - frame->chunk->code - 1].line,
-                    .col = frame->chunk->lines[vm->pc - frame->chunk->code - 1].col,
-                });
-                return;
+                RUNTIME_ERROR(ERR_NOT_IMPLEMENTED);
             } break;
         }
     }
-- 
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