class IStringConsumer inherits System {
	init() : IStringConsumer {
		self
	};

	consume(s: String) : Int {
		not_implemented_retint("consume")
	};

	token() : IToken {{
		not_implemented("token");
		new IToken;
	}};

	out() : Object {
		not_implemented("out")
	};

---
	consumed_length: Int;
	consumed_length() : Int {
		consumed_length
	};
};