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