factor out a call_func function

lib/vm/vm.c

 	}
 }
 
+// The 'call_func' function assumes that all relevant values have been popped off
+// the stack, so that the return value can be pushed to the top of the stack
+// straight away
+static void call_func(
+		struct l2_vm *vm, l2_word func_id,
+		l2_word argc, l2_word *argv) {
+	l2_word stack_base = vm->sptr;
+
+	struct l2_vm_value *func = &vm->values[func_id];
+	enum l2_value_type typ = l2_vm_value_type(func);
+
+	// C functions are called differently from language functions
+	if (typ == L2_VAL_TYPE_CFUNCTION) {
+		vm->stack[vm->sptr++] = func->cfunc(vm, argc, argv);
+		return;
+	}
+
+	// Don't interpret a non-function as a function
+	if (typ != L2_VAL_TYPE_FUNCTION) {
+		vm->stack[vm->sptr++] = l2_vm_error(vm, "Attempt to call non-function");
+		return;
+	}
+
+	l2_word arr_id = alloc_val(vm);
+	vm->values[arr_id].flags = L2_VAL_TYPE_ARRAY;
+	vm->values[arr_id].array = malloc(
+			sizeof(struct l2_vm_array) + sizeof(l2_word) * argc);
+	struct l2_vm_array *arr = vm->values[arr_id].array;
+	arr->len = argc;
+	arr->size = argc;
+
+	for (l2_word i = 0; i < argc; ++i) {
+		arr->data[i] = argv[i];
+	}
+
+	vm->stack[vm->sptr++] = arr_id;
+
+	l2_word ns_id = alloc_val(vm);
+	func = &vm->values[func_id]; // func might be stale after alloc
+	vm->values[ns_id].extra.ns_parent = func->func.ns;
+	vm->values[ns_id].ns = NULL;
+	vm->values[ns_id].flags = L2_VAL_TYPE_NAMESPACE;
+	vm->fstack[vm->fsptr].ns = ns_id;
+	vm->fstack[vm->fsptr].retptr = vm->iptr;
+	vm->fstack[vm->fsptr].sptr = stack_base;
+	vm->fsptr += 1;
+
+	vm->iptr = func->func.pos;
+}
+
 void l2_vm_step(struct l2_vm *vm) {
 	enum l2_opcode opcode = (enum l2_opcode)vm->ops[vm->iptr++];
 
 			l2_word *argv = vm->stack + vm->sptr;
 
 			l2_word func_id = vm->stack[--vm->sptr];
-			struct l2_vm_value *func = &vm->values[func_id];
-
-			l2_word stack_base = vm->sptr;
-			enum l2_value_type typ = l2_vm_value_type(func);
-
-			// C functions are called differently from language functions
-			if (typ == L2_VAL_TYPE_CFUNCTION) {
-				vm->stack[vm->sptr++] = func->cfunc(vm, argc, argv);
-				break;
-			}
-
-			// Don't interpret a non-function as a function
-			if (typ != L2_VAL_TYPE_FUNCTION) {
-				vm->stack[vm->sptr++] = l2_vm_error(vm, "Attempt to call non-function");
-				break;
-			}
-
-			l2_word arr_id = alloc_val(vm);
-			vm->values[arr_id].flags = L2_VAL_TYPE_ARRAY;
-			vm->values[arr_id].array = malloc(
-					sizeof(struct l2_vm_array) + sizeof(l2_word) * argc);
-			struct l2_vm_array *arr = vm->values[arr_id].array;
-			arr->len = argc;
-			arr->size = argc;
-
-			for (l2_word i = 0; i < argc; ++i) {
-				arr->data[i] = argv[i];
-			}
-
-			vm->stack[vm->sptr++] = arr_id;
-
-			l2_word ns_id = alloc_val(vm);
-			func = &vm->values[func_id]; // func might be stale after alloc
-			vm->values[ns_id].extra.ns_parent = func->func.ns;
-			vm->values[ns_id].ns = NULL;
-			vm->values[ns_id].flags = L2_VAL_TYPE_NAMESPACE;
-			vm->fstack[vm->fsptr].ns = ns_id;
-			vm->fstack[vm->fsptr].retptr = vm->iptr;
-			vm->fstack[vm->fsptr].sptr = stack_base;
-			vm->fsptr += 1;
-
-			vm->iptr = func->func.pos;
+			call_func(vm, func_id, argc, argv);
 		}
 		break;
 
 			l2_word func_id = vm->stack[--vm->sptr];
 			l2_word lhs = vm->stack[--vm->sptr];
 
-			struct l2_vm_value *func = &vm->values[func_id];
-
-			l2_word stack_base = vm->sptr;
-			enum l2_value_type typ = l2_vm_value_type(func);
-
-			// C functions are called differently from language functions
-			if (typ == L2_VAL_TYPE_CFUNCTION) {
-				l2_word argv[] = { lhs, rhs };
-				vm->stack[vm->sptr++] = func->cfunc(vm, 2, argv);
-				break;
-			}
-
-			// Don't interpret a non-function as a function
-			if (typ != L2_VAL_TYPE_FUNCTION) {
-				vm->stack[vm->sptr++] = l2_vm_error(vm, "Attempt to call non-function");
-				break;
-			}
-
-			l2_word arr_id = alloc_val(vm);
-			vm->values[arr_id].flags = L2_VAL_TYPE_ARRAY;
-			vm->values[arr_id].array = malloc(
-					sizeof(struct l2_vm_array) + sizeof(l2_word) * 2);
-			struct l2_vm_array *arr = vm->values[arr_id].array;
-			arr->len = 2;
-			arr->size = 2;
-			arr->data[0] = lhs;
-			arr->data[1] = rhs;
-
-			vm->stack[vm->sptr++] = arr_id;
-
-			l2_word ns_id = alloc_val(vm);
-			func = &vm->values[func_id]; // func might be stale after alloc
-			vm->values[ns_id].extra.ns_parent = func->func.ns;
-			vm->values[ns_id].ns = NULL;
-			vm->values[ns_id].flags = L2_VAL_TYPE_NAMESPACE;
-			vm->fstack[vm->fsptr].ns = ns_id;
-			vm->fstack[vm->fsptr].retptr = vm->iptr;
-			vm->fstack[vm->fsptr].sptr = stack_base;
-			vm->fsptr += 1;
-
-			vm->iptr = func->func.pos;
+			l2_word argv[] = {lhs, rhs};
+			call_func(vm, func_id, 2, argv);
 		}
 		break;