From: Michael Heerdegen <michael_heerdegen@web.de>
To: Damien Cassou <damien@cassou.me>
Cc: help-gnu-emacs@gnu.org
Subject: Re: Using the content of a dynamic variable in a macro
Date: Sun, 26 Feb 2023 12:47:57 +0100 [thread overview]
Message-ID: <87sfesbqc2.fsf@web.de> (raw)
In-Reply-To: <871qmftvzs.fsf@cassou.me> (Damien Cassou's message of "Fri, 24 Feb 2023 07:31:35 +0100")
Damien Cassou <damien@cassou.me> writes:
> I'm wondering why the code below works but won't compile.
>
> foo.el:
> (defvar foo-var '((message "hello world")))
>
> (defmacro foo-macro ()
> `(progn
> ,@foo-var))
>
> (defun foo-fun ()
> (foo-macro))
> [...]
> foo.el:32:1: Error: Symbol’s value as variable is void: foo-var
>
> Why isn't the compiler aware of the foo-var variable?
The compiler is aware of it, but it doesn't eval the definition. It is
a feature that the compiler normally does not load any part of the
program when compiling, including variable definitions. Note that in
the general case, evaluating a defvar form might require to load more
parts of a file, or even the complete file.
If you do need to eval something when compiling, use `eval-when-compile'
or `eval-and-compile' respectively.
Michael.
next prev parent reply other threads:[~2023-02-26 11:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-24 6:31 Using the content of a dynamic variable in a macro Damien Cassou
2023-02-26 11:47 ` Michael Heerdegen [this message]
-- strict thread matches above, loose matches on Subject: below --
2023-02-25 8:34 Damien Cassou
2023-02-25 9:38 ` Eli Zaretskii
2023-02-25 9:43 ` Damien Cassou
2023-02-25 12:32 ` Lynn Winebarger
2023-02-27 3:24 ` Richard Stallman
2023-02-27 19:05 ` Basil Contovounesios
2023-02-28 2:44 ` Lynn Winebarger
2023-02-25 9:40 ` tomas
2023-02-27 19:03 ` Basil Contovounesios
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87sfesbqc2.fsf@web.de \
--to=michael_heerdegen@web.de \
--cc=damien@cassou.me \
--cc=help-gnu-emacs@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.