:- protocol(objectp).
:- info([
version is 1.0,
author is 'Paulo Moura',
date is 2000/7/24,
comment is 'Default protocol for all objects.']).
:- public(strict_instance/0).
:- mode(strict_instance, zero_or_one).
:- info(strict_instance/0, [
comment is 'True if the object is strictly an instance.']).
:- public(print/0).
:- mode(print, one).
:- info(print/0, [
comment is 'Pretty prints an object description.']).
:- public(nil/0).
:- mode(nil, zero_or_one).
:- info(nil/0, [
comment is 'True if the object represents a void reference.']).
:- end_protocol.