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Revision 3565, 0.9 KB
(checked in by pmoura, 21 months ago)
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Split mode directive of between/3 in two more specific ones.
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Property svn:eol-style set to
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Property svn:keywords set to
Author Date Id Revision
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| 1 | |
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| 2 | :- object(integer, |
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| 3 | extends(number)). |
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| 4 | |
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| 5 | :- info([ |
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| 6 | version is 1.1, |
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| 7 | author is 'Paulo Moura', |
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| 8 | date is 2007/4/20, |
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| 9 | comment is 'Integer data type predicates.']). |
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| 10 | |
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| 11 | :- public(between/3). |
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| 12 | :- mode(between(+integer, +integer, +integer), zero_or_one). |
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| 13 | :- mode(between(+integer, +integer, -integer), zero_or_more). |
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| 14 | :- info(between/3, [ |
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| 15 | comment is 'Returns integers in the interval defined by the two first arguments.', |
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| 16 | argnames is ['Lower', 'Upper', 'Integer']]). |
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| 17 | |
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| 18 | between(Lower, Upper, Integer) :- |
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| 19 | integer(Lower), |
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| 20 | integer(Upper), |
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| 21 | ( var(Integer) -> |
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| 22 | Lower =< Upper, |
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| 23 | generate(Lower, Upper, Integer) |
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| 24 | ; integer(Integer), |
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| 25 | Lower =< Integer, |
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| 26 | Integer =< Upper |
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| 27 | ). |
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| 28 | |
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| 29 | generate(Lower, _, Lower). |
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| 30 | generate(Lower, Upper, Integer) :- |
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| 31 | Lower < Upper, |
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| 32 | Next is Lower + 1, |
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| 33 | generate(Next, Upper, Integer). |
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| 34 | |
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| 35 | valid(Integer) :- |
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| 36 | integer(Integer). |
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| 37 | |
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| 38 | :- end_object. |
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