From: Elena <egarrulo@gmail.com>
To: help-gnu-emacs@gnu.org
Subject: Re: Redefining functions and variables
Date: Thu, 29 Jul 2010 01:32:06 -0700 (PDT) [thread overview]
Message-ID: <08217e84-b4a0-4dd0-afbf-abd4d762c759@w30g2000yqw.googlegroups.com> (raw)
In-Reply-To: 87hbjjibrk.fsf@kuiper.lan.informatimago.com
On Jul 28, 8:37 pm, p...@informatimago.com (Pascal J. Bourguignon)
wrote:
> Andreas Politz <poli...@fh-trier.de> writes:
> > Elena <egarr...@gmail.com> writes:
>
> >> On Jul 28, 7:51 am, Elena <egarr...@gmail.com> wrote:
> >>> > Of course this leads to an endless recursive loop, expanding your macro
> >>> > again and again ...
>
> >>> Then I should have tested the macro with `macroexpand-all' instead of
> >>> `macroexpand'. However, I've tried using the macro, and it seemed to
> >>> work, albeit it choked on the unquoted symbol passed to `fboundp'.
>
> >> I think it seemed to work because the macro was interpreted, therefore
> >> it was expanded only once before the failure.
>
> > Don't know, but defining `defun' as a macro usually deletes the original
> > subst (which is a special form, which is kind of like a macro).
>
> > (defvar defun-subst (symbol-function 'defun))
>
> > (defmacro defun (name args &rest body)
> > `(defun ,name ,args ,@body))
>
> > (defun foo ())
> > ;; Enters the debugger because of recursion limit reached.
>
> > ;; Restore original defun
> > (fset 'defun defun-subst)
>
> Another way:
>
> (defvar old-defun 'defun) ; the symbol!
> (unintern 'defun)
>
> (defmacro defun (name args &rest body)
> `(progn
> (message "defining %S" name)
> (,old-defun ,name ,args ,@body)))
This is very close to what I was looking for. Thanks, Pascal.
My modified macro is below. Why ',name is expanded as ... (as shown by
`macroexpand-all'?
(defvar old-defun 'defun) ; the symbol!
(unintern 'defun)
(defmacro defun (name args &rest body)
`(progn
;; `load-file-name' is not null only if we are loading a
file.
(when (and load-file-name
(fboundp ',name))
(message "Warning: %s is being redefined in %s."
(symbol-name ',name)
load-file-name)
(,old-defun ,name ,args
,@body))))
next prev parent reply other threads:[~2010-07-29 8:32 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-27 15:12 Redefining functions and variables Elena
2010-07-27 20:21 ` Stefan Monnier
2010-07-27 22:16 ` Elena
2010-07-28 0:35 ` Andreas Politz
2010-07-28 7:51 ` Elena
2010-07-28 14:29 ` Elena
2010-07-28 18:48 ` Andreas Politz
2010-07-28 20:37 ` Pascal J. Bourguignon
2010-07-29 8:32 ` Elena [this message]
2010-07-29 9:57 ` Stefan Monnier
2010-07-29 10:16 ` Elena
2010-07-29 13:14 ` Stefan Monnier
2010-07-30 19:32 ` Uday S Reddy
2010-07-29 10:31 ` Andreas Politz
2010-07-29 11:46 ` Johan Bockgård
2010-07-29 15:54 ` Andreas Politz
2010-07-29 12:41 ` Tim X
2010-07-29 10:03 ` Pascal J. Bourguignon
2010-07-29 10:28 ` Elena
2010-07-29 20:35 ` Johan Bockgård
2010-07-29 22:22 ` Tim X
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