From: Lute Kamstra <Lute.Kamstra.lists@xs4all.nl>
Cc: emacs-devel@gnu.org
Subject: Re: Problems with debug-on-entry in the Lisp debugger.
Date: Mon, 07 Mar 2005 16:20:55 +0100 [thread overview]
Message-ID: <876503wkh4.fsf@xs4all.nl> (raw)
In-Reply-To: <87hdjnegak.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Mon, 07 Mar 2005 08:31:48 -0500")
Stefan Monnier <monnier@iro.umontreal.ca> writes:
>> I can think of two points in a macro to set a break for the
>> debugger: just before macro expansion and just after it, right
>> before the evaluation of the resulting sexp. In both cases,
>> hiding the debug-on-entry code from the user of the debugger
>> seems not possible.
>
> To me "entry of a macro" is very clearly "just before expansion".
> Especially if you think of macro-expansion occurring because of
> explicit calls to macroexpand (e.g. in the byte-compiler) rather
> than as a direct part of interpretation.
I see you implemented this. This makes debug-on-entry for macros a
lot better, of course. Thanks. But the problem I mentioned remains:
the debug-entry-code is visible. For example:
(defmacro inc (var)
(list 'setq var (list '1+ var)))
(debug-on-entry 'inc)
(progn (setq x 0) (inc x))
gives a backtrace like this:
------ Buffer: *Backtrace* ------
Debugger entered--entering a function:
* (lambda (var) (if (or inhibit-debug-on-entry debugger-jumping-flag) nil (debug ...)) (list (quote setq) var (list ... var)))(x)
(inc x)
(progn (setq x 0) (inc x))
eval((progn (setq x 0) (inc x)))
eval-last-sexp-1(nil)
eval-last-sexp(nil)
call-interactively(eval-last-sexp)
------ Buffer: *Backtrace* ------
>> Shall I go ahead and try to implement this, or do people think this
>> is a bad idea?
>
> I think it's a bad idea. The interpreter is already way too slow,
> I'd rather not make it worse.
I think the effect on performance will be very minimal. Do you know
of a good way to test the performance of the interpreter so that I can
measure the impact of my proposed change? Can you indicate how much
performance loss would be acceptable for you?
Lute.
next prev parent reply other threads:[~2005-03-07 15:20 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-07 11:05 Problems with debug-on-entry in the Lisp debugger Lute Kamstra
2005-03-07 13:31 ` Stefan Monnier
2005-03-07 15:20 ` Lute Kamstra [this message]
2005-03-07 16:32 ` Stefan Monnier
2005-03-08 18:57 ` Lute Kamstra
2005-03-09 16:58 ` Richard Stallman
2005-03-09 17:30 ` Lute Kamstra
2005-03-07 13:40 ` Kim F. Storm
2005-03-07 14:20 ` drkm
2005-03-07 14:45 ` Kim F. Storm
2005-03-08 2:53 ` Richard Stallman
2005-03-08 18:02 ` Lute Kamstra
2005-03-08 18:59 ` Stefan Monnier
2005-03-09 10:14 ` Lute Kamstra
2005-03-09 16:58 ` Richard Stallman
2005-03-09 16:58 ` Richard Stallman
2005-03-09 17:38 ` Lute Kamstra
2005-03-10 0:26 ` Kevin Rodgers
2005-03-11 1:47 ` Richard Stallman
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