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Logtalk - Object oriented extension to Prolog
Release 2.9.2
Copyright (c) 1998-2002 Paulo Moura. All Rights Reserved.
% some queries dealing with instance/class hierarchies:
| ?- object::ancestors(Ancestors).
Ancestors = [class, abstract_class, object]
Yes
| ?- class::instances(Instances).
Instances = [object, abstract_class, class]
| ?- class::superclass(Super).
Super = abstract_class ;
Super = object ;
No