%   File   : IMISCE.PL
%   Author : Lawrence Byrd, L. Hardman
%   Updated: 4 April 1984
%   Purpose: Miscellaneous routines (interpreted)

%   The contents of this module should be redistributed.  The only thing
%   which has to be interpreted rather than compiled is subgoal, and that
%   is incomplete and obsolete.  gcc needs once from INVOCA.PL.

:- public
	(\=)/2,
	casserta/1,
	cassertz/1,
	clean/0,
	continue/0.


continue.			%  This is one of the actions for error/3


\=(X, X) :- !,
	fail.
\=(X, Y) :- !.


casserta(X) :-
	clause(X, true),
	!.
casserta(X) :-
	asserta(X).


cassertz(X) :-
	clause(X, true),
	!.
cassertz(X) :-
	assertz(X).


clean :-
	nolog,
	seeing(OldInput),
	see('prolog.log'),
	rename('prolog.log', []),
	seen,
	see(OldInput),
	log.


diff(X, X) :- !,
	fail.
diff(X, Y).


gcc(Goal) :-
	once(Goal),
	asserta('$gcc'(Goal)),
	fail.
gcc(Goal) :-
	retract('$gcc'(Answer)),
	!,		%  This cut is needed for nested 
	Goal = Answer.


l(X) :- listing(X).			% Make listing easier.


subgoal(exact, L) :-
	\+ \+ (numbervars(L, 0, _), subgoal_of(L) ).