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Re: use of (defvar <foo>)
From: |
Stefan Monnier |
Subject: |
Re: use of (defvar <foo>) |
Date: |
Fri, 07 Apr 2006 16:45:43 -0400 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux) |
> Could people on emacs-devel please comment on this?
> Should we use (defvar <foo>) or (eval-when-compile (defvar <foo>)) in Gnus
> for compatibility with Emacs 21? (Probably the same holds for MH-E.)
>From the future's point of view (Emacs-22 and up), placing such defvars
inside eval-when-compile is a bad practice (in the future it may even fail
to work since there's nothing that guarantees that the content of
eval-when-compile is actually compiled rather than just eval'd).
In Emacs-21 and older, such a defvar will have some undesirable minor
side-effects (via the load-history) unless it is placed inside an
eval-when-compile *and* the file is byte-compiled. Indeed placing the
defvar inside the eval-when-compile has no effect if the file is not
byte-compiled.
I'd recommend to not use eval-when-compile since that's what many packages
have been doing for many years without suffering much (if ever) of the
occasional side-effects (which only affect unload-feature and sometimes
C-h v).
But it's your call, really.
Stefan
- Re: use of (defvar <foo>), Reiner Steib, 2006/04/07
- Re: use of (defvar <foo>),
Stefan Monnier <=
- Re: use of (defvar <foo>), Bill Wohler, 2006/04/07
- Re: use of (defvar <foo>), Dave Love, 2006/04/09
- Re: use of (defvar <foo>), Stefan Monnier, 2006/04/09
- Re: use of (defvar <foo>), Dave Love, 2006/04/11
- Re: use of (defvar <foo>), David Kastrup, 2006/04/11
- Re: use of (defvar <foo>), Dave Love, 2006/04/13
- Re: use of (defvar <foo>), Stefan Monnier, 2006/04/11
- Re: use of (defvar <foo>), Dave Love, 2006/04/13