53 lines
1.2 KiB
Plaintext
53 lines
1.2 KiB
Plaintext
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:- object(rectangle(_width, _height, _position),
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imports(private::assignvars)).
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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 2005/1/8,
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comment is 'A simple implementation of a geometric rectangle using assignable variables and parametric objects.',
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parnames is ['Width', 'Height', 'Position']]).
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:- public(init/0).
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:- mode(init, one).
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:- info(init/0,
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[comment is 'Initialize rectangle position.']).
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:- public(area/1).
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:- mode(area(-integer), one).
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:- info(area/1,
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[comment is 'Rectangle area.',
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argnames is ['Area']]).
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:- public(move/2).
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:- mode(move(+integer, +integer), one).
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:- info(move/2, [
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comment is 'Moves a rectangle to a new position.',
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argnames is ['X', 'Y']]).
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:- public(position/2).
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:- mode(position(?integer, ?integer), zero_or_one).
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:- info(position/2, [
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comment is 'Rectangle current position.',
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argnames is ['X', 'Y']]).
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init :-
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parameter(3, Position),
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::assignable(Position, (0, 0)).
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area(Area) :-
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parameter(1, Width),
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parameter(2, Height),
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Area is Width*Height.
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move(X, Y) :-
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parameter(3, Position),
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::Position <= (X, Y).
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position(X, Y) :-
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parameter(3, Position),
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::Position => (X, Y).
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:- end_object.
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