6b4bde14e1
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1903 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
39 lines
875 B
Plaintext
39 lines
875 B
Plaintext
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:- object(integer,
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extends(number)).
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:- info([
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version is 1.1,
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author is 'Paulo Moura',
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date is 2007/4/20,
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comment is 'Integer data type predicates.']).
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:- public(between/3).
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:- mode(between(+integer, +integer, +integer), zero_or_one).
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:- mode(between(+integer, +integer, -integer), zero_or_more).
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:- info(between/3, [
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comment is 'Returns integers in the interval defined by the two first arguments.',
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argnames is ['Lower', 'Upper', 'Integer']]).
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between(Lower, Upper, Integer) :-
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integer(Lower),
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integer(Upper),
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( var(Integer) ->
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Lower =< Upper,
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generate(Lower, Upper, Integer)
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; integer(Integer),
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Lower =< Integer,
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Integer =< Upper
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).
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generate(Lower, _, Lower).
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generate(Lower, Upper, Integer) :-
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Lower < Upper,
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Next is Lower + 1,
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generate(Next, Upper, Integer).
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valid(Integer) :-
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integer(Integer).
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:- end_object.
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