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yap-6.3/pl/lists.yap

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2013-11-26 09:40:00 +00:00
2013-11-26 09:53:04 +00:00
:- '$set_yap_flags'(11,1). % source.
2013-11-26 09:40:00 +00:00
% memberchk(+Element, +Set)
% means the same thing, but may only be used to test whether a known
% Element occurs in a known Set. In return for this limited use, it
% is more efficient when it is applicable.
lists:memberchk(X,[X|_]) :- !.
lists:memberchk(X,[_|L]) :-
lists:memberchk(X,L).
% member(?Element, ?Set)
% is true when Set is a list, and Element occurs in it. It may be used
% to test for an element or to enumerate all the elements by backtracking.
% Indeed, it may be used to generate the Set!
lists:member(X,[X|_]).
lists:member(X,[_|L]) :-
lists:member(X,L).
lists:append([], L, L).
lists:append([H|T], L, [H|R]) :-
lists:append(T, L, R).
2013-11-26 09:53:04 +00:00
:- '$set_yap_flags'(11,0). % :- no_source.