| 1 | |
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| 2 | :- category(subject). |
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| 3 | |
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| 4 | :- info([ |
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| 5 | version is 1.0, |
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| 6 | author is 'Paulo Moura', |
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| 7 | date is 03/02/09, |
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| 8 | comment is 'Smalltalk dependent handling predicates.']). |
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| 9 | |
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| 10 | :- public(changed/0). |
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| 11 | :- mode(changed, one). |
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| 12 | :- info(changed/0, |
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| 13 | [comment is 'Receiver changed in some way. Notify all dependents.']). |
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| 14 | |
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| 15 | :- public(changed/1). |
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| 16 | :- mode(changed(?nonvar), one). |
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| 17 | :- info(changed/1, |
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| 18 | [comment is 'Receiver changed as specified in the argument. Notify all dependents.', |
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| 19 | argnames is ['Change']]). |
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| 20 | |
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| 21 | :- public(dependents/1). |
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| 22 | :- mode(dependents(-list), one). |
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| 23 | :- info(dependents/1, |
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| 24 | [comment is 'Returns a list of all dependent objects.', |
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| 25 | argnames is ['Dependents']]). |
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| 26 | |
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| 27 | :- private(dependent_/1). |
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| 28 | :- dynamic(dependent_/1). |
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| 29 | :- mode(dependent_(?object), zero_or_more). |
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| 30 | :- info(dependent_/1, |
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| 31 | [comment is 'Dependent object table.', |
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| 32 | argnames is ['Dependent']]). |
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| 33 | |
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| 34 | :- public(addDependent/1). |
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| 35 | :- mode(addDependent(@object), one). |
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| 36 | :- info(addDependent/1, |
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| 37 | [comment is 'Adds a new dependent object.', |
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| 38 | argnames is ['Dependent']]). |
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| 39 | |
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| 40 | :- public(removeDependent/1). |
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| 41 | :- mode(removeDependent(?object), zero_or_more). |
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| 42 | :- info(removeDependent/1, |
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| 43 | [comment is 'Removes a dependent object.', |
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| 44 | argnames is ['Dependent']]). |
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| 45 | |
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| 46 | changed :- |
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| 47 | self(Self), |
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| 48 | forall(::dependent_(Dependent), Dependent::update(Self)). |
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| 49 | |
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| 50 | changed(Change) :- |
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| 51 | forall(::dependent_(Dependent), Dependent::update(Change)). |
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| 52 | |
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| 53 | dependents(Dependents) :- |
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| 54 | findall(Dependent, ::dependent_(Dependent), Dependents). |
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| 55 | |
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| 56 | addDependent(Dependent) :- |
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| 57 | ::dependent_(Dependent) -> |
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| 58 | true |
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| 59 | ; |
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| 60 | ::asserta(dependent_(Dependent)). |
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| 61 | |
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| 62 | removeDependent(Dependent) :- |
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| 63 | ::retract(dependent_(Dependent)). |
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| 64 | |
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| 65 | :- end_category. |
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