Chapter 29.1

This commit is contained in:
Tom Willemse 2022-08-14 20:14:43 -07:00
parent 62858b60e4
commit 726803c9d0
4 changed files with 30 additions and 4 deletions

View file

@ -38,6 +38,7 @@ typedef enum {
OP_CLOSE_UPVALUE,
OP_RETURN,
OP_CLASS,
OP_INHERIT,
OP_METHOD,
} OpCode;

View file

@ -474,6 +474,10 @@ static void namedVariable(Token name, bool canAssign) {
}
}
static void variable(bool canAssign) {
namedVariable(parser.previous, canAssign);
}
static void classDeclaration() {
consume(TOKEN_IDENTIFIER, "Expect class name");
Token className = parser.previous;
@ -487,6 +491,18 @@ static void classDeclaration() {
classCompiler.enclosing = currentClass;
currentClass = &classCompiler;
if (match(TOKEN_LESS)) {
consume(TOKEN_IDENTIFIER, "Expect superclass name.");
variable(false);
if (identifiersEqual(&className, &parser.previous)) {
error("A class can't inherit from itself.");
}
namedVariable(className, false);
emitByte(OP_INHERIT);
}
namedVariable(className, false);
consume(TOKEN_LEFT_BRACE, "Expect '{' before class body.");
while (!check(TOKEN_RIGHT_BRACE) && !check(TOKEN_EOF)) {
@ -722,10 +738,6 @@ static void string(bool canAssign) {
copyString(parser.previous.start + 1, parser.previous.length - 2)));
}
static void variable(bool canAssign) {
namedVariable(parser.previous, canAssign);
}
static void this_(bool canAssign) {
if (currentClass == NULL) {
error("Can't use 'this' outside of a class.");

View file

@ -139,6 +139,8 @@ int disassembleInstruction(Chunk *chunk, int offset) {
return simpleInstruction("OP_RETURN", offset);
case OP_CLASS:
return constantInstruction("OP_CLASS", chunk, offset);
case OP_INHERIT:
return simpleInstruction("OP_INHERIT", offset);
case OP_METHOD:
return constantInstruction("OP_METHOD", chunk, offset);
default:

View file

@ -496,6 +496,17 @@ static InterpretResult run() {
case OP_CLASS:
push(OBJ_VAL(newClass(READ_STRING())));
break;
case OP_INHERIT: {
Value superclass = peek(1);
if (!IS_CLASS(superclass)) {
runtimeError("Superclass must be a class.");
return INTERPRET_RUNTIME_ERROR;
}
ObjClass *subclass = AS_CLASS(peek(0));
tableAddAll(&AS_CLASS(superclass)->methods, &subclass->methods);
pop(); /* Subclass. */
break;
}
case OP_METHOD:
defineMethod(READ_STRING());
break;