ENHANCED: Delay toplevel output until after the goal succeeds.
ENHANCED: Delay toplevel output until after the goal succeeds.

This is to accommodate goals that are used for their side-effects,
when we are interested in their output.

Examples:

    ?- portray_clause((a :- a)).
    a :-
            a.
       true
    ;  false.

    ?- format("hello~w~n", [!]).
    hello!
       true
    ;  false.

mthom/rusty-wam