%------------------------------------------------------------------------
% Program that used to give wrong results.
%
% Model T = {q,r}, F = {p}, U = {}.
%------------------------------------------------------------------------

% :- auto_table.
:- table p/0, q/0, r/0.

p :- tnot(q), p.
r :- tnot(p), q.
q :- tnot(p).

%------------------------------------------------------------------------

test :- r, fail.
test :- ( p ->	( tnot(p) -> writeln('p is undefined')
		; writeln('p is true') )
	; writeln('p is false (OK)') ),
        ( q ->  ( tnot(q) -> writeln('q is undefined')
		; writeln('q is true (OK)') )
	; writeln('q is false') ),
	( r ->  ( tnot(r) -> writeln('r  is undefined')
		; writeln('r is true (OK)') )
	; writeln('r  is false') ).