34 lines
848 B
Plaintext
34 lines
848 B
Plaintext
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/* Circle is a special form of ellipse */
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/* Subclasses ('circle' here) must have the same number of arguments */
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/* as their superclass ('ellipse') for the superclass predicates to */
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/* be applicable. The arguments may be renamed for clarity. */
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:- object(circle(Center, Radius),
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extends(ellipse(Center, Radius, Radius))).
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:- info([
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authors is 'Paulo Moura',
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version is 1.0,
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date is 2000/4/22,
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comment is 'Parametric object for representing geometric circles.',
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parnames is ['Center', 'Radius'],
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source is 'Example adopted from the POEM system by Ben Staveley-Taylor.']).
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:- public(circumference/1).
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:- mode(circumference(-number), one).
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circumference(Circumference) :-
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pi(Pi),
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parameter(2, Radius),
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Circumference is 2*Pi*Radius.
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pi(3.14196).
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:- end_object.
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