cc4531cd1e
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@53 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
25 lines
353 B
Plaintext
25 lines
353 B
Plaintext
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:- object(natural,
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extends(integer)).
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:- info([
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version is 1.0,
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authors is 'Paulo Moura',
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date is 2000/7/24,
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comment is 'Natural numbers data type predicates.']).
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between(Lower, Upper, Integer) :-
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integer(Lower),
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Lower > 0,
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^^between(Lower, Upper, Integer).
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valid(Natural) :-
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integer(Natural),
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Natural > 0.
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:- end_object.
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