Hello, How do I trace the evaluation of a predicate only when a specified set of arguments is passed to this predicate? So far I have been using spy(my_predicate) to creep through the evaluation of my_predicate during program execution. However, this has recently become tedious as there are numero…

[image] aminemarref: Is there another trick up your sleeve? Just use n(odebug) (c(ontinue) in the non-GUI tracer) or l(eap)? The next time it traps gtrace it will restart tracing. Note that leap implies debug mode. The debug mode pushes a dummy choice point for each otherwise determinis…

Not sure if the SWI-Prolog graphical debugger supports such functionality…? In case your Prolog code can be wrapped by a Logtalk object (or in case it’s a module that Logtalk is able to compile as an object), you may be able to use the Logtalk debugger context spy points to only spy a specific pred…

[image] aminemarref: How do I trace the evaluation of a predicate only when a specified set of arguments is passed to this predicate? That isn’t really provided. There are two alternatives. If you can point at a specific place in the code you can use the built-in editor facilities to place …

Thank you @pmoura :slight_smile: I will look into using this option once I have exhausted (in vain) all SWI-specific debug features to solve my issue.

Thank you @jan , I have used the conditional tracing as you kindly suggested: (condition_on_values_of_MyArg -> trace; true) So now I am able to get directly to the desired predicate with the desired arguments. Now, can I “leap” to the next evaluation of my_predicate with arguments MyArg? Adding a…

[image] aminemarref: SWI-specific debug features I try to collect them in Wiki: Bug hunting toolbox

[image] jan: With the recently added wrap_predicate/4 we could add conditional spy points easily. Not sure what it is worth though. I often find myself adding a test inside a predicate, e.g. my_pred(A,B,C) :- ( some_test(A) -> trace ; true ), % added for debugging % the rest of the …

There’s also prolog_trace_interception which probably could be packaged in a friendlier way for specific action at a goal. My guess is that something like this should work (untested): prolog_trace_interception(call, Frame, _Choice, Action) :- prolog_frame_attribute(Frame, goal, Module:Goal), …

To some extend that can work. One of the problems is that it will cause a huge slowdown by forcing debug mode and going through this hook at practically all steps. The skip is probably wrong as this would prevent a conditional debug in a deeper nested call. There is wrap_predicate/4 which make…

Debugging: Tracing the Execution of a Specific Goal

Help!

EricGT September 9, 2019, 1:00pm 6

I try to collect them in Wiki: Bug hunting toolbox

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Debugging: Tracing the Execution of a Specific Goal

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