% nacteni:
/* ['2.1.1_3.pl']. */
% vymaz predchozi deklarace member
:- retractall(member/2).
:- dynamic member/2.
member(X,[X|_]).
member(X,[_|T]) :- member(X,T).
% demonstracni vypis
% abychom se vyhli varovanim "Redefined static procedure ..."
:- dynamic
write_all_X/3,
start/0.
write_all_X(Goal,X,Name):-
call(Goal),write(' '),write(Name),write(' = '),write(X),nl,fail.
write_all_X(_,_,_).
start:-
write('Member - 1. varianta'),nl,
write('Vysledek volani "member(a,[X,b,c])" je:'),nl,
write_all_X(member(a,[X,b,c]), X, 'X').
?-start.
:- retractall(write_all_X/3).
:- retractall(start/0).
Member - 1. varianta
Vysledek volani "member(a,[X,b,c])" je:
X = a