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yap-6.3/Logtalk/library/set.lgt
2001-06-06 19:40:57 +00:00

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:- object(set,
implements(setp),
extends(compound)).
:- info([
version is 1.0,
authors is 'Paulo Moura',
date is 2000/7/24,
comment is 'Set predicates implemented using ordered lists. Uses ==/2 for element comparison and standard term ordering.']).
delete([], _, []).
delete([Head| Tail], Element, Remaining) :-
compare(Order, Head, Element),
delete(Order, Head, Tail, Element, Remaining).
delete(=, _, Tail, _, Tail).
delete(<, Head, Tail, Element, [Head| Tail2]) :-
delete(Tail, Element, Tail2).
delete(>, _, Tail, _, Tail).
disjoint([], _) :- !.
disjoint(_, []) :- !.
disjoint([Head1| Tail1], [Head2| Tail2]) :-
compare(Order, Head1, Head2),
disjoint(Order, Head1, Tail1, Head2, Tail2).
disjoint(<, _, Tail1, Head2, Tail2) :-
disjoint(Tail1, [Head2| Tail2]).
disjoint(>, Head1, Tail1, _, Tail2) :-
disjoint([Head1| Tail1], Tail2).
equal(Set1, Set2) :-
Set1 == Set2.
empty(Set) :-
Set == [].
insert([], Element, [Element]).
insert([Head| Tail], Element, Set) :-
compare(Order, Head, Element),
insert(Order, Head, Tail, Element, Set).
insert(<, Head, Tail, Element, [Head| Set]) :-
insert(Tail, Element, Set).
insert(=, Head, Tail, _, [Head| Tail]).
insert(>, Head, Tail, Element, [Element, Head| Tail]).
insert_all([], Set, Set).
insert_all([Head| Tail], Set1, Set3) :-
insert(Set1, Head, Set2),
insert_all(Tail, Set2, Set3).
intersect([Head1| Tail1], [Head2| Tail2]) :-
compare(Order, Head1, Head2),
intersect(Order, Head1, Tail1, Head2, Tail2).
intersect(=, _, _, _, _).
intersect(<, _, Tail1, Head2, Tail2) :-
intersect(Tail1, [Head2| Tail2]).
intersect(>, Head1, Tail1, _, Tail2) :-
intersect([Head1| Tail1], Tail2).
intersection(_, [], []) :- !.
intersection([], _, []) :- !.
intersection([Head1| Tail1], [Head2| Tail2], Intersection) :-
compare(Order, Head1, Head2),
intersection(Order, Head1, Tail1, Head2, Tail2, Intersection).
intersection(=, Head, Tail1, _, Tail2, [Head| Intersection]) :-
intersection(Tail1, Tail2, Intersection).
intersection(<, _, Tail1, Head2, Tail2, Intersection) :-
intersection(Tail1, [Head2| Tail2], Intersection).
intersection(>, Head1, Tail1, _, Tail2, Intersection) :-
intersection([Head1|Tail1], Tail2, Intersection).
length(Set, Length) :-
length(Set, 0, Length).
length([], Length, Length).
length([_| Set], Acc, Length) :-
Acc2 is Acc + 1,
length(Set, Acc2, Length).
member(Element, Set) :-
var(Element) ->
member_var(Element, Set)
;
member_nonvar(Element, Set).
member_var(Element, [Element| _]).
member_var(Element, [_| Set]) :-
member_var(Element, Set).
member_nonvar(Element, [Head| Tail]):-
compare(Order, Element, Head),
member_nonvar(Order, Element, Tail).
member_nonvar(=, _, _).
member_nonvar(>, Element, [Head| Tail]) :-
compare(Order, Element, Head),
member_nonvar(Order, Element, Tail).
new([]).
powerset(Set, PowerSet):-
reverse(Set, RSet),
powerset_1(RSet, [[]], PowerSet).
powerset_1([], PowerSet, PowerSet).
powerset_1([X| Xs], Yss0, Yss):-
powerset_2(Yss0, X, Yss1),
powerset_1(Xs, Yss1, Yss).
powerset_2([], _, []).
powerset_2([Zs| Zss], X, [Zs, [X| Zs]| Yss]):-
powerset_2(Zss, X, Yss).
reverse(List, Reversed) :-
reverse(List, [], Reversed).
reverse([], Reversed, Reversed).
reverse([Head| Tail], List, Reversed) :-
reverse(Tail, [Head| List], Reversed).
select(Head, [Head| Tail], Tail).
select(Head, [Head2| Tail], [Head2| Tail2]) :-
select(Head, Tail, Tail2).
subset([], _) :- !.
subset([Head1| Tail1], [Head2| Tail2]) :-
compare(Order, Head1, Head2),
subset(Order, Head1, Tail1, Head2, Tail2).
subset(=, _, Tail1, _, Tail2) :-
subset(Tail1, Tail2).
subset(>, Head1, Tail1, _, Tail2) :-
subset([Head1| Tail1], Tail2).
subtract(Set, [], Set) :- !.
subtract([], _, []) :- !.
subtract([Head1| Tail1], [Head2| Tail2], Difference) :-
compare(Order, Head1, Head2),
subtract(Order, Head1, Tail1, Head2, Tail2, Difference).
subtract(=, _, Tail1, _, Tail2, Difference) :-
subtract(Tail1, Tail2, Difference).
subtract(<, Head1, Tail1, Head2, Tail2, [Head1| Difference]) :-
subtract(Tail1, [Head2| Tail2], Difference).
subtract(>, Head1, Tail1, _, Tail2, Difference) :-
subtract([Head1| Tail1], Tail2, Difference).
symdiff(Set, [], Set) :- !.
symdiff([], Set, Set) :- !.
symdiff([Head1| Tail1], [Head2| Tail2], Difference) :-
compare(Order, Head1, Head2),
symdiff(Order, Head1, Tail1, Head2, Tail2, Difference).
symdiff(=, _, Tail1, _, Tail2, Difference) :-
symdiff(Tail1, Tail2, Difference).
symdiff(<, Head1, Tail1, Head2, Tail2, [Head1| Difference]) :-
symdiff(Tail1, [Head2| Tail2], Difference).
symdiff(>, Head1, Tail1, Head2, Tail2, [Head2| Difference]) :-
symdiff([Head1| Tail1], Tail2, Difference).
union(Set, [], Set) :- !.
union([], Set, Set) :- !.
union([Head1| Tail1], [Head2| Tail2], Union) :-
compare(Order, Head1, Head2),
union(Order, Head1, Tail1, Head2, Tail2, Union).
union(=, Head, Tail1, _, Tail2, [Head| Union]) :-
union(Tail1, Tail2, Union).
union(<, Head1, Tail1, Head2, Tail2, [Head1| Union]) :-
union(Tail1, [Head2| Tail2], Union).
union(>, Head1, Tail1, Head2, Tail2, [Head2| Union]) :-
union([Head1| Tail1], Tail2, Union).
valid(Set) :-
nonvar(Set),
valid2(Set).
valid2([]) :-
!.
valid2([_]) :-
!.
valid2([Element1, Element2| Set]) :-
Element1 @< Element2,
valid2([Element2| Set]).
:- end_object.