copy method
Returns a shallow copy of the receiver.
Override this method in all subclasses, return its own type.
Implementation
@override
CastParser<R, S> copy() => CastParser<R, S>(delegate);
Returns a shallow copy of the receiver.
Override this method in all subclasses, return its own type.
@override
CastParser<R, S> copy() => CastParser<R, S>(delegate);