The following conditions are for prescribing or checking the
breakpoint type. They cause an exception if used outside the
debugger or in execution_state/2
.
advice
debugger
The following construct converts an arbitrary Prolog goal into a condition.
true(
Cond)
once(
Cond)
is executed and the condition is satisfied iff this completes
successfully. If an exception is raised during execution, then an error
message is printed and the condition fails.
The substitutions done on executing Cond are carried out. Cond is subject to module name expansion. If used in the test part of spypoint conditions, the goal should not have any side-effects, as the test part may be evaluated several times.
The following conditions represent the Boolean constants.
true
[]
false