From: Stefan Monnier <monnier@iro.umontreal.ca>
To: help-gnu-emacs@gnu.org
Subject: Re: How do you pre-evaluate a function passed to a macro?
Date: Sat, 14 Nov 2009 03:18:25 -0500 [thread overview]
Message-ID: <jwvocn5ed0e.fsf-monnier+gnu.emacs.help@gnu.org> (raw)
In-Reply-To: mailman.10640.1258121962.2239.help-gnu-emacs@gnu.org
> I'm calling a function, wanting to pass nil instead of the empty string
> when the string argument is zero length. But the function is defined as
> a macro, so the argument gets passed in unevaluated, which fails.
> How do I force evaluation of the argument before it is passed in?
> --8<---------------cut here---------------start------------->8---
> ;; myname is a string taken from user input
> (bbdb-search (bbdb-records) (if (> (length myname) 0) myname nil) nil
> nil)
(if (> (length myname) 0)
(bbdb-search (bbdb-records) myname nil nil)
(bbdb-search (bbdb-records) nil nil nil))
Stefan
next prev parent reply other threads:[~2009-11-14 8:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.10640.1258121962.2239.help-gnu-emacs@gnu.org>
2009-11-13 17:01 ` How do you pre-evaluate a function passed to a macro? Barry Margolin
2009-11-14 8:18 ` Stefan Monnier [this message]
2009-11-13 14:18 Gregory J. Grubbs
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