66 lines
1.6 KiB
Plaintext
66 lines
1.6 KiB
Plaintext
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:- category(subject).
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:- info([
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version is 1.0,
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author is 'Paulo Moura',
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date is 03/02/09,
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comment is 'Smalltalk dependent handling predicates.']).
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:- public(changed/0).
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:- mode(changed, one).
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:- info(changed/0,
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[comment is 'Receiver changed in some way. Notify all dependents.']).
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:- public(changed/1).
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:- mode(changed(?nonvar), one).
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:- info(changed/1,
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[comment is 'Receiver changed as specified in the argument. Notify all dependents.',
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argnames is ['Change']]).
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:- public(dependents/1).
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:- mode(dependents(-list), one).
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:- info(dependents/1,
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[comment is 'Returns a list of all dependent objects.',
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argnames is ['Dependents']]).
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:- private(dependent_/1).
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:- dynamic(dependent_/1).
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:- mode(dependent_(?object), zero_or_more).
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:- info(dependent_/1,
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[comment is 'Dependent object table.',
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argnames is ['Dependent']]).
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:- public(addDependent/1).
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:- mode(addDependent(@object), one).
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:- info(addDependent/1,
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[comment is 'Adds a new dependent object.',
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argnames is ['Dependent']]).
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:- public(removeDependent/1).
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:- mode(removeDependent(?object), zero_or_more).
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:- info(removeDependent/1,
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[comment is 'Removes a dependent object.',
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argnames is ['Dependent']]).
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changed :-
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self(Self),
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forall(::dependent_(Dependent), Dependent::update(Self)).
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changed(Change) :-
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forall(::dependent_(Dependent), Dependent::update(Change)).
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dependents(Dependents) :-
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findall(Dependent, ::dependent_(Dependent), Dependents).
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addDependent(Dependent) :-
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::dependent_(Dependent) ->
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true
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;
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::asserta(dependent_(Dependent)).
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removeDependent(Dependent) :-
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::retract(dependent_(Dependent)).
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:- end_category.
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