48 lines
1.0 KiB
Plaintext
48 lines
1.0 KiB
Plaintext
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:- object(root, % avoid infinite metaclass regression by
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instantiates(root)). % making the class its own metaclass
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:- public(method/0).
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method :-
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this(This),
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write('This is the default definition for the method, stored in class '),
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writeq(This), write('.'), nl.
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:- end_object.
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:- object(instance1, % this instance simply inherits the method/0 predicate
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instantiates(root)).
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:- end_object.
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:- object(instance2, % this instance provides its own definition for the
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instantiates(root)). % method/0 predicate
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method :-
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this(This),
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write('This is an overriding definition stored in the '),
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writeq(This),
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write(' instance itself.'), nl.
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:- end_object.
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:- object(instance3, % this instance specializes the inherited definition
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instantiates(root)). % of the method/0 predicate
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method :-
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this(This),
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write('This is a specializing definition stored in the '),
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writeq(This),
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write(' instance itself.'), nl,
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write('It makes a super call to execute the default definition:'), nl, nl,
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^^method.
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:- end_object.
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