member/3
Gets or checks a member of a list and its position
member(Term,List,Position) -(i,i,o),(o,i,i),(o,i,o)
?Term <term>
?List <list> or <variable>
?Position <integer> or <variable>
Compatibility: LPA Win-Prolog.
Remarks:
1) This predicate succeeds when its first argument is bound to a Term which is a member of the List bound to the second argument, and its third argument is bound to this element's Position. The second argument may be a fully or partially instantiated list, or simply a variable; member/3 can backtrack to generate alternative solutions where appropriate.