"Neil Jerram" wrote: > Out of interest, though, what changes would you like to the > presentation?
If you are referring to the documentation draft: I think it is fine. If you are referring to the stack trace I posted: I would like it to be the same as for a 'common' error: with the section > <unnamed port>: In procedure gsl-ode-evolve in expression > (gsl-p-ode-evolve ode initial-indep-value ...): > <unnamed port>: my error message 1 and 2 displayed at the bottom, below all the stack frames. I do not think that it is easy to do: I obtain the stack trace by recording the stack at the moment of error, and then using the lower section of it as part of the error message. Splitting a stack and appending a section to another seems a dirty thing (I do not know how a stack is implemented, though). "Neil Jerram" wrote: >do you think that the way my Emacs interface displays the >stack is better or worse than this? >http://www.ossau.uklinux.net/guile/debugging-demo/shot2.html I dunno. It has a completely different purpose. Nice one that there is a stepping debugger, though. "Neil Jerram" wrote: >"Marco Maggi" wrote: >> and that the args content is not explicitly documented >> even if its content is well defined in 'scm_error_scm()': >> >> scm_ithrow (key, >> scm_list_4 (subr, message, args, data), 1); > >Yes, here I completely agree with you. I do not have enough experience to be authoritative on exception handling. :) I want to make clear that the 'args' I am referring to is the 'args' handed to the 'scm_t_catch_handler handler' function, parameter of 'scm_c_catch()'. This 'args' ends up being the: scm_list_4 (subr, message, args, data) list; this value is exception independent. I want this 'args' created by 'scm_error_scm()' to be officially documented so that there is a constraint on keeping compatibility. :) I do not think that this list needs to be changed; maybe a helper function that formats the string could be useful, so that one can avoid putting: scm_simple_format(s_port, s_message, (scm_is_eq(SCM_BOOL_F, s_args)? SCM_EOL : s_args)); in the code, as I have done, to build the message. "Ludovic Courts" wrote: >Indeed, this exception model is not very convenient. In >some cases, it's even hardly usable, as examplified by the >`test-suite/lib.scm' hacks (use of regexps to parse >exception messages and determine their meaning...). But applications and test suites are different scenarios. "Ludovic Courts" wrote: >Ideally, Guile should use some SRFI-3[56]-like mechanism to >represent exceptions. SRFI-35 defines a complex value, maybe too complex. It is not clear to me if a fine-grained hierarchy of exception descriptors can really improve the quality of the code. There are two classes of exceptions: logic and runtime. Logic are the problems that I should have removed at debugging time, I do not think that it is possible to try to recover from those. Runtime are state synchronisations. How can the application recover from a state synchronisation exception? One aborts the transaction and/or frees asynchronous resources allocated for the operation. Is there a significant number of real-world cases in which one can retry the operation without aborting/freeing? Should it be possible to do something without breaking compatibility by generalising the 'key' argument and use upon it a generalised version of 'equal?'? -- Marco Maggi "They say jump!, you say how high?" Rage Against the Machine - "Bullet in the Head" _______________________________________________ Guile-user mailing list Guile-user@gnu.org http://lists.gnu.org/mailman/listinfo/guile-user