diff --git a/lang/main.c b/lang/main.c
index 059db8b..030511b 100644
--- a/lang/main.c
+++ b/lang/main.c
@@ -9,7 +9,8 @@
 	struct object *numA = number_create(5);
 	struct object *numB = number_create(3);
 	struct object *args[] = {numB};
-	struct object *numC = dispatch_call(numA, "Add", 1, &args[0]);
+	dispatch_call(numA, "Add", 1, &args[0]);
+	struct object *numC = args[0];
 	printf("numC value is %i\n", number_value(numC));
 	printf("numA is %p\n", (void *)numA);
 	printf("numB is %p\n", (void *)numB);
diff --git a/lang/number.c b/lang/number.c
index 3f2dc8f..e5f5f31 100644
--- a/lang/number.c
+++ b/lang/number.c
@@ -36,8 +36,7 @@
 	return num->value;
 }
 
-struct object *number_add(
-	struct object *obj, int arg_count, struct object **args) {
+void number_add(struct object *obj, int arg_count, struct object **args) {
 	abort_if(arg_count != 1, "number_add called with more than 1 argument");
 	abort_if(!args[0], "number_add arg is NULL");
 	abort_if(obj->class_data != &num_class,
@@ -47,7 +46,7 @@
 	struct number *numA = (struct number *)obj;
 	struct number *numB = (struct number *)args[0];
 	int added = numA->value + numB->value;
-	return number_create(added);
+	args[0] = number_create(added);
 }
 
 struct object_call calls[] = {
diff --git a/lang/number.h b/lang/number.h
index 4f3a5d7..376b605 100644
--- a/lang/number.h
+++ b/lang/number.h
@@ -13,6 +13,6 @@
 int number_value(struct object *);
 
 // Adds two numbers together
-struct object *number_add(struct object *, struct object *);
+void number_add(struct object *, struct object *);
 
 #endif
diff --git a/lang/object.c b/lang/object.c
index 62907ad..0995679 100644
--- a/lang/object.c
+++ b/lang/object.c
@@ -20,12 +20,13 @@
 	*objptr = NULL;
 }
 
-struct object *dispatch_call(struct object *obj, const char *name,
-	int arg_count, struct object **args) {
+void dispatch_call(struct object *obj, const char *name, int arg_count,
+	struct object **args) {
 	struct object_call *call = obj->class_data->calls;
 	while (call->name != NULL) {
 		if (strcmp(call->name, name) == 0) {
-			return call->handler(obj, arg_count, args);
+			call->handler(obj, arg_count, args);
+			return;
 		}
 		++call;
 	}
diff --git a/lang/object.h b/lang/object.h
index 2cf37c9..dc4be25 100644
--- a/lang/object.h
+++ b/lang/object.h
@@ -20,7 +20,7 @@
 // Dispatchable object call
 struct object_call {
 	const char *name;
-	struct object *(*handler)(
+	void (*handler)(
 		struct object *obj, int arg_count, struct object **args);
 };
 
@@ -36,7 +36,7 @@
 void object_drop(struct object **objptr);
 
 // Calls a method on an object
-struct object *dispatch_call(struct object *obj, const char *name,
-	int arg_count, struct object **args);
+void dispatch_call(struct object *obj, const char *name, int arg_count,
+	struct object **args);
 
 #endif