Chapter 26.7

clox/src/chunk.c

@@ -2,6 +2,7 @@
 
 #include "chunk.h"
 #include "memory.h"
+#include "vm.h"
 
 void initChunk(Chunk *chunk) {
   chunk->count = 0;
@@ -22,7 +23,8 @@ void writeChunk(Chunk* chunk, uint8_t byte, int line) {
   if (chunk->capacity < chunk->count + 1) {
     int oldCapacity = chunk->capacity;
     chunk->capacity = GROW_CAPACITY(oldCapacity);
-    chunk->code = GROW_ARRAY(uint8_t, chunk->code, oldCapacity, chunk->capacity);
+    chunk->code =
+        GROW_ARRAY(uint8_t, chunk->code, oldCapacity, chunk->capacity);
     chunk->lines = GROW_ARRAY(int, chunk->lines, oldCapacity, chunk->capacity);
   }
 
@@ -32,6 +34,8 @@ void writeChunk(Chunk* chunk, uint8_t byte, int line) {
 }
 
 int addConstant(Chunk *chunk, Value value) {
+  push(value);
   writeValueArray(&chunk->constants, value);
+  pop();
   return chunk->constants.count - 1;
 }

clox/src/object.c

@@ -58,7 +58,11 @@ static ObjString *allocateString(char *chars, int length, uint32_t hash) {
   string->length = length;
   string->chars = chars;
   string->hash = hash;
+
+  push(OBJ_VAL(string));
   tableSet(&vm.strings, string, NIL_VAL);
+  pop();
+
   return string;
 }
 

clox/src/vm.c

@@ -163,8 +163,8 @@ static bool isFalsey(Value value) {
 }
 
 static void concatenate() {
-  ObjString *b = AS_STRING(pop());
-  ObjString *a = AS_STRING(pop());
+  ObjString *b = AS_STRING(peek(0));
+  ObjString *a = AS_STRING(peek(1));
 
   int length = a->length + b->length;
   char *chars = ALLOCATE(char, length + 1);
@@ -173,6 +173,8 @@ static void concatenate() {
   chars[length] = '\0';
 
   ObjString *result = takeString(chars, length);
+  pop();
+  pop();
   push(OBJ_VAL(result));
 }