git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1232 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
		
			
				
	
	
		
			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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