/* lists.plg: list processing predicates */
/* David Harvey 18/1/89 */

/*-----------------------------

import with 
    [lists].

------------------------------*/

/* isempty */
	isempty([]).

/* append */
	append([],L,L).
	append([X|L1],L2,[X|L3]) :-
		append(L1,L2,L3).

/* membership rule */
	member(X,[X|_]).
	member(X,[_|Y]) :- 
		member(X,Y).

/* writelist */
	writelist([]).
	writelist([H|T]) :-
		write(H),
		writelist(T).

/* last */
	last(X,[X]).
	last(X,[_|Y]) :-
		last(X,Y).

/* first */
	first(X,[X|_]).


/* EOF lists.pl */	ist(T).

/* last */
	last(X,[X]).
	last(X,[_|Y]) :-
		l