From: "Óscar Fuentes" <ofv@wanadoo.es>
To: emacs-devel@gnu.org
Subject: Wierd Elispsisms (was: trunk r113793: lisp/*.el: More lexical-binding warnings' cleanups.)
Date: Sun, 11 Aug 2013 13:16:40 +0200 [thread overview]
Message-ID: <87iozcmq93.fsf@wanadoo.es> (raw)
In-Reply-To: E1V8JCW-0006AY-BZ@vcs.savannah.gnu.org
Juanma Barranquero <lekktu@gmail.com> writes:
[elisp/woman.el]
@@ -1614,7 +1614,7 @@
(let* ((bufname (file-name-nondirectory file-name))
(case-fold-search t)
(compressed
- (not (not (string-match woman-file-compression-regexp bufname)))))
+ (and (string-match-p woman-file-compression-regexp bufname) t)))
(if compressed
(setq bufname (file-name-sans-extension bufname)))
The expressions
(not (not (something)))
and
(and (something-p) t)
look bizarre. As someone who is not strong on Elisp, I was puzzled at
first. Finally realized that the point is to force a boolean value for
`compressed'.
Why is so important to use a nil/t value for `compressed'?
And, if there exists a reason for using nil/t instead of the original
value here and elsewhere, why doesn't exist a function for casting an
arbitrary value to a boolean?
Using (and ... t) or (not (not ...)) is probably not harder to type than
a function, but the function has the advantage of clearly conveying the
intention and is safer to edit.
next parent reply other threads:[~2013-08-11 11:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <E1V8JCW-0006AY-BZ@vcs.savannah.gnu.org>
2013-08-11 11:16 ` Óscar Fuentes [this message]
2013-08-11 11:41 ` Wierd Elispsisms (was: trunk r113793: lisp/*.el: More lexical-binding warnings' cleanups.) Juanma Barranquero
2013-08-11 22:33 ` Wierd Elispsisms Óscar Fuentes
2013-08-11 18:28 ` trunk r113793: lisp/*.el: More lexical-binding warnings' cleanups Glenn Morris
2013-08-12 15:12 ` Juanma Barranquero
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=87iozcmq93.fsf@wanadoo.es \
--to=ofv@wanadoo.es \
--cc=emacs-devel@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.