Re: [Maxima-discuss] Debugging maxima

[Michel T. <ta...@lp...>]

Le 19/07/2025 à 18:36, Robert Dodier a écrit :
> Setting breakpoints isn't straightforward, from what I know. Here's my
> clumsy workaround.


Like Robert i have not found the lisp debugger of gcl usable. I think 
the first step to debug something in maxima is to use a maxima compiled 
with sbcl. Then to set breakpoints at entry of a function one can use 
the sbcl extension of the trace function such as:

:lisp (trace 'some-function' :break true)

If one wants to single step the program one must first recompile it 
setting some

(declaim (optimize (debug 3)))

at its beginning.  The at the breakpoint one can say first: start which 
starts tracing and the commands like step to single step, etc. One then 
gets something very close to what gdb allows.

Here are some extracts from sbcl documentation: (describe 'trace)

        :BREAK Form
        :BREAK-AFTER Form
        :BREAK-ALL Form
            If specified, and Form evaluates to true, then the debugger 
is invoked
            at the start of the function, at the end of the function, or 
both,
            according to the respective option.

and for the debugger, printing *DEBUG-HELP-STRING*

Inspecting frames:
   BACKTRACE [n]  shows n frames going down the stack.
   LIST-LOCALS, L lists locals in current frame.
   PRINT, P       displays function call for current frame.
   SOURCE [n]     displays frame's source form with n levels of 
enclosing forms.

Stepping:
   START Selects the CONTINUE restart if one exists and starts
         single-stepping. Single stepping affects only code compiled with
         under high DEBUG optimization quality. See User Manual for details.
   STEP  Steps into the current form.
   NEXT  Steps over the current form.
   OUT   Stops stepping temporarily, but resumes it when the topmost 
frame that
         was stepped into returns.
   STOP  Stops single-stepping.



-- 
Michel Talon