:- import set_pil_on/0,set_pil_off/0,
	tfindall/3,abolish_table_pred/1  from tables.
:- import numbervars/3 from num_vars.

:- table c/2.
:- table d/2.
:- table e/2.

member(X,[X|_]).
member(X,[_|List]):-member(X,List).

testcombo:-   c(W,E),T = c(W,E),numbervars(T,0,_),writeq(T),nl,fail
	   ;  d(W,E),T = d(W,E),numbervars(T,0,_),writeq(T),nl,fail
	   ; true.

tc1:-d(W,E),T = d(W,E),numbervars(T,0,_T1),writeq(T),nl,fail.
tc1.

tc2:-e(W,E),T = e(W,E),numbervars(T,0,_T1),writeq(T),nl,fail.

c(X,Y):-p(X,Y).
c(X,Y):-p(X,Z),
	tfindall(Yprime,c(Z,Yprime),Ylist),member(Y,Ylist).

d(X,Y):-p(X,Y).
d(X,Y):-p(X,Z),
	d(Z,_),tfindall(Yprime,d(Z,Yprime),Ylist),
	member(Y,Ylist).
d(X,Y):-p(X,Z),
	tfindall(Yprime,d(Z,Yprime),Ylist),member(Y,Ylist).

e(X,Y):-p(X,Y).
e(X,Y):-p(X,Z),
	e(Z,_),tfindall(Yprime,e(Z,Yprime),Ylist),
	member(Y,Ylist).
%e(X,Y):-p(X,Z),
%	tfindall(Yprime,e(Z,Yprime),Ylist),member(Y,Ylist).

p(1,2).
p(1,7).
p(2,3).
p(3,4).
p(4,5).
p(4,15).
p(7,8).
p(7,18).
p(8,9).
p(8,10).