portray_term(?Term, -TransTerm, +As)

Term

A term.

TransTerm

A variable.

As

One of the atoms 'term', 'goal' or 'clause'

Description

This predicate is intended mainly for testing purposes, because portray-transformations are normally performed implicitly by the term output predicates write/1,2, writeln/1,2, print/1,2, display/1,2, printf/2,3 or write_term/2,3.

Modes and Determinism

• portray_term(?, -, +) is det

Modules

Examples

    % Given the program:

        :- local portray(s/1, tr_s/2, []).
        tr_s(0, 0).
        tr_s(s(S), N) :- tr_s(S, N1), N is N1+1.


    % Implicit portray transformation by write/1:
    ?- S = s(s(s(0))), write(S).
    3
    yes.

    % Explicit portray transformation
    % Note: no transformation done by writeq/1
    ?- S = s(s(s(0))), writeq(S), portray_term(S, P, term), writeq(P).
    s(s(s(0)))
    3
    yes.

See Also