PLOGHELP ARG                                  Chris Mellish, August 1982
                                Revised by Kathryn Seifert  October 1986

Predicate which determines the Nth argument of a given term

    ?- arg(N, Term, Arg).

Keywords: term, arguments, structure


A goal of the form
    ?- arg(N, Term, Arg).
will succeed if the  Nth  argument in Term is Arg.  Both N and Term
must be instantiated.

For example:

    ?- arg(3, foo(a, b, c, d), A).
    A = c ?

-- RELATED DOCUMENTATION ----------------------------------------------

PLOGHELP * FUNCTOR
 Predicate which constructs a term with a given functor and arity

PLOGHELP * DOLLAR
 Library package for using variables to hold predicate names