Chapter 28.4

1 files changed, 21 insertions, 2 deletions

diff --git a/clox/src/compiler.c b/clox/src/compiler.c
index a773e97..4dded64 100644
--- a/clox/src/compiler.c
+++ b/clox/src/compiler.c
@@ -51,7 +51,12 @@ typedef struct {
   bool isLocal;
 } Upvalue;
 
-typedef enum { TYPE_FUNCTION, TYPE_METHOD, TYPE_SCRIPT } FunctionType;
+typedef enum {
+  TYPE_FUNCTION,
+  TYPE_INITIALIZER,
+  TYPE_METHOD,
+  TYPE_SCRIPT
+} FunctionType;
 
 typedef struct Compiler {
   struct Compiler *enclosing;
@@ -159,7 +164,12 @@ static int emitJump(uint8_t instruction) {
 }
 
 static void emitReturn() {
-  emitByte(OP_NIL);
+  if (current->type == TYPE_INITIALIZER) {
+    emitBytes(OP_GET_LOCAL, 0);
+  } else {
+    emitByte(OP_NIL);
+  }
+
   emitByte(OP_RETURN);
 }
 
@@ -389,6 +399,11 @@ static void method() {
   uint8_t constant = identifierConstant(&parser.previous);
 
   FunctionType type = TYPE_METHOD;
+  if (parser.previous.length == 4 &&
+      memcmp(parser.previous.start, "init", 4) == 0) {
+    type = TYPE_INITIALIZER;
+  }
+
   function(type);
   emitBytes(OP_METHOD, constant);
 }
@@ -588,6 +603,10 @@ static void returnStatement() {
   if (match(TOKEN_SEMICOLON)) {
     emitReturn();
   } else {
+    if (current->type == TYPE_INITIALIZER) {
+      error("Can't return a value from an initializer.");
+    }
+
     expression();
     consume(TOKEN_SEMICOLON, "Expect ';' after return value.");
     emitByte(OP_RETURN);