GNU bug report logs - #6985
rx patterns don't compose

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Package: emacs;

Reported by: Daniel Colascione <dan.colascione <at> gmail.com>

Date: Sat, 4 Sep 2010 23:37:02 UTC

Severity: wishlist

Tags: fixed, patch

Merged with 36237

Fixed in version 27.1

Done: Noam Postavsky <npostavs <at> gmail.com>

Bug is archived. No further changes may be made.

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From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Daniel Colascione <dan.colascione <at> gmail.com>
Cc: 6985 <at> debbugs.gnu.org
Subject: bug#6985: rx patterns don't compose
Date: Sun, 05 Sep 2010 09:22:04 +0200

> It's not possible to do this currently:
> (defconst foo-re (rx "abc"))
> (defconst bar-re (rx (* (what-goes-here? foo-re)))

(defconst foo-re (rx "abc"))
(defconst bar-re `(rx (* (regexp ,foo-re)))


> in any sensible way. This won't work

>   (defconst bar-re (rx (* (regexp foo-re))))

> because regexp always expects a string.

> This won't work, because eval always quotes its argument:

>   (defconst bar-re (rx (* (eval foo-re))))

> I propose allowing regexp to accept a symbol as well as a string, and
> using that symbol's value literally. Alternatively, rx could provide an
> eval-unquoted facility. Or both.

eval-unquoted sounds OK


        Stefan
This bug report was last modified 5 years and 327 days ago.

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