projog

3.59. spy(X) / nospy(X) - add or remove a spy point for a predicate.

spy(X) - add a spy point for a predicate. By adding a spy point for the predicate name instantiated to X the programmer will be informed how it is used in the resolution of a goal.

nospy(X) - removes a spy point for a predicate. By removing a spy point for the predicate name instantiated to X the programmer will no longer be informed how it is used in the resolution of a goal.

Examples