58 lines
1.1 KiB
Plaintext
58 lines
1.1 KiB
Plaintext
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:- object(sort(_Type)).
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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 'List sorting parameterized by the type of the list elements.',
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parnames is ['Type'],
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source is 'Example adopted from the SICStus Objects documentation.']).
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:- uses(list).
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:- calls(comparingp).
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:- public(sort/2).
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:- mode(sort(+list, -list), one).
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:- info(sort/2, [
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comment is 'Sorts a list in ascending order.',
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argnames is ['List', 'Sorted']]).
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:- private(partition/4).
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:- mode(partition(+list, +nonvar, -list, -list), one).
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:- info(partition/4, [
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comment is 'List partition in two sub-lists using a pivot.',
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argnames is ['List', 'Pivot', 'Lowers', 'Biggers']]).
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sort([], []).
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sort([P| L], S) :-
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partition(L, P, Small, Large),
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sort(Small, S0),
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sort(Large, S1),
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list::append(S0, [P| S1], S).
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partition([], _, [], []).
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partition([X| L1], P, Small, Large) :-
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parameter(1, Type),
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( Type::(X < P) ->
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Small = [X| Small1], Large = Large1
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; Small = Small1, Large = [X| Large1]
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),
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partition(L1, P, Small1, Large1).
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:- end_object.
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