Use a variable as predicate?

[Neophyte1981]

Is there a way to use a variable as a predicate?

For instance

test(Pred, Var) :- Pred(Var).

Then asking

test(not, true).

should yield false. Is this is possible? Do I need to use an eval() type function?

With kind regards, Patrick

 

[joel76]

You can do this kind of thing :

mult(X, Y) :-
	Y is 2 * X.

test(Pred, Var, Result) :-
	call(Pred, Var, Result).

test(Pred, Var) :-
	writeln(before),
	call(Pred, Var),
	writeln(after).


test :-
	test(mult, 2, Z),
	writeln(Z),
	test(not, false),
	test(not, true).

The output is :
6 ?- test.
4
before
after
before
false.

Is-it what you want ?

 

[Neophyte1981]

It wotrks like a charm!

Thank you for your quick and accurate reply joel76!

Patrick