// Validates that the given argument in [args] is a function. Returns true if
// it is. If not, reports an error and returns false.
static bool validateFn(WrenVM* vm, Value* args, int index, const char* argName)
{
if (IS_FN(args[index]) || IS_CLOSURE(args[index])) return true;
args[0] = OBJ_VAL(wrenStringConcat(vm, argName, " must be a function."));
return false;
}
// Validates that the given argument in [args] is a Num. Returns true if it is.
// If not, reports an error and returns false.
static bool validateNum(WrenVM* vm, Value* args, int index, const char* argName)
{
if (IS_NUM(args[index])) return true;
args[0] = OBJ_VAL(wrenStringConcat(vm, argName, " must be a number."));
return false;
}
// Validates that [value] is an integer. Returns true if it is. If not, reports
// an error and returns false.
static bool validateIntValue(WrenVM* vm, Value* args, double value,
const char* argName)
{
if (trunc(value) == value) return true;
args[0] = OBJ_VAL(wrenStringConcat(vm, argName, " must be an integer."));
return false;
}
// Validates that [value] is an integer within `[0, count)`. Also allows
// negative indices which map backwards from the end. Returns the valid positive
// index value. If invalid, reports an error and returns -1.
static int validateIndexValue(WrenVM* vm, Value* args, int count, double value,
const char* argName)
{
if (!validateIntValue(vm, args, value, argName)) return -1;
int index = (int)value;
// Negative indices count from the end.
if (index < 0) index = count + index;
// Check bounds.
if (index >= 0 && index < count) return index;
args[0] = OBJ_VAL(wrenStringConcat(vm, argName, " out of bounds."));
return -1;
}
ObjClass* wrenNewClass(WrenVM* vm, ObjClass* superclass, int numFields,
ObjString* name)
{
WREN_PIN(vm, name);
// Create the metaclass.
ObjString* metaclassName = wrenStringConcat(vm, name->value, " metaclass");
WREN_PIN(vm, metaclassName);
ObjClass* metaclass = wrenNewSingleClass(vm, 0, metaclassName);
metaclass->obj.classObj = vm->classClass;
WREN_UNPIN(vm);
// Make sure the metaclass isn't collected when we allocate the class.
WREN_PIN(vm, metaclass);
// Metaclasses always inherit Class and do not parallel the non-metaclass
// hierarchy.
wrenBindSuperclass(vm, metaclass, vm->classClass);
ObjClass* classObj = wrenNewSingleClass(vm, numFields, name);
// Make sure the class isn't collected while the inherited methods are being
// bound.
WREN_PIN(vm, classObj);
classObj->obj.classObj = metaclass;
wrenBindSuperclass(vm, classObj, superclass);
WREN_UNPIN(vm);
WREN_UNPIN(vm);
WREN_UNPIN(vm);
return classObj;
}
