From 62858b60e43803477e898c7993e109a94701ce70 Mon Sep 17 00:00:00 2001
From: Tom Willemse
Date: Sun, 14 Aug 2022 19:56:32 -0700
Subject: Chapter 28.5

---
 clox/src/vm.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

(limited to 'clox/src/vm.c')

diff --git a/clox/src/vm.c b/clox/src/vm.c
index d248609..b5cb1cc 100644
--- a/clox/src/vm.c
+++ b/clox/src/vm.c
@@ -146,6 +146,33 @@ static bool callValue(Value callee, int argCount) {
   return false;
 }
 
+static bool invokeFromClass(ObjClass *klass, ObjString *name, int argCount) {
+  Value method;
+  if (!tableGet(&klass->methods, name, &method)) {
+    runtimeError("Undefined property '%s'.", name->chars);
+    return false;
+  }
+  return call(AS_CLOSURE(method), argCount);
+}
+
+static bool invoke(ObjString *name, int argCount) {
+  Value receiver = peek(argCount);
+
+  if (!IS_INSTANCE(receiver)) {
+    runtimeError("Only instances have methods.");
+    return false;
+  }
+
+  ObjInstance *instance = AS_INSTANCE(receiver);
+
+  Value value;
+  if (tableGet(&instance->fields, name, &value)) {
+    vm.stackTop[-argCount - 1] = value;
+    return callValue(value, argCount);
+  }
+  return invokeFromClass(instance->klass, name, argCount);
+}
+
 static bool bindMethod(ObjClass *klass, ObjString *name) {
   Value method;
   if (!tableGet(&klass->methods, name, &method)) {
@@ -424,6 +451,15 @@ static InterpretResult run() {
       frame = &vm.frames[vm.frameCount - 1];
       break;
     }
+    case OP_INVOKE: {
+      ObjString *method = READ_STRING();
+      int argCount = READ_BYTE();
+      if (!invoke(method, argCount)) {
+        return INTERPRET_RUNTIME_ERROR;
+      }
+      frame = &vm.frames[vm.frameCount - 1];
+      break;
+    }
     case OP_CLOSURE: {
       ObjFunction *function = AS_FUNCTION(READ_CONSTANT());
       ObjClosure *closure = newClosure(function);
-- 
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