Sets spypoints on all the predicates represented by PredSpecs
Turns debugger on in debug mode, so that it will stop as soon as it
reaches a spypoint. Turning off the debugger does not remove
nospyall/0) to explicitly remove
Note that since
spy is a built-in operator, the parentheses, which usually
surround the arguments to a predicate, are not necessary (although they can be
used if desired).
If you use the predicate specification form Name but there are no clauses for Name (of any arity), then a warning message will be displayed and no spypoint will be set.
| ?- spy test. % The debugger will first leap -- showing spypoints (debug) * There are no predicates with the name test in module user yes [debug]
To place a spypoint on a currently undefined procedure, use the full form Name/Arity; you will still get a warning message, but the spypoint will be set .
| ?- spy test/1. * You have no clauses for user:test/1 % Spypoint placed on user:test/1 yes [debug] | ?-
spy/1 is given any invalid argument it prints a warning.
This predicate is not supported in runtime systems.