From: Alan Mackenzie <acm@muc.de>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: emacs-devel@gnu.org
Subject: Re: Fwd: Re: Inadequate documentation of silly characters on screen.
Date: Thu, 19 Nov 2009 17:08:38 +0000 [thread overview]
Message-ID: <20091119170838.GC1314@muc.de> (raw)
In-Reply-To: <jwvmy2ieix7.fsf-monnier+emacs@gnu.org>
Hi, Stefan,
On Thu, Nov 19, 2009 at 09:08:29AM -0500, Stefan Monnier wrote:
> >> If you give us more context (i.e. more of the real code where the
> >> problem show up), maybe we can tell you how to avoid it.
> > OK. I have my own routine to display regexps. As a first step, I
> > translate \n -> ñ, (and \t, \r, \f similarly). This is how:
> > (defun translate-rnt (regexp)
> > "REGEXP is a string. Translate any \t \n \r and \f characters
> > to wierd non-ASCII printable characters: \t to Î (206, \xCE), \n
> > to ñ (241, \xF1), \r to ® (174, \xAE) and \f to £ (163, \xA3).
> > The original string is modified."
> > (let (ch pos)
> > (while (setq pos (string-match "[\t\n\r\f]" regexp))
> > (setq ch (aref regexp pos))
> > (aset regexp pos ; <===================
> > (cond ((eq ch ?\t) ?Î)
> > ((eq ch ?\n) ?ñ)
> > ((eq ch ?\r) ?®)
> > (t ?£))))
> > regexp))
> Each one of those `aset' (when performed according to your wishes) would
> change the byte-size of the string, so it would internally require
> copying the whole string each time: aset on (multibyte) strings is very
> inefficient (compared to what most people expect, not necessarily
> compared to other operations). I'd recommend you use higher-level
> operations since they'll work just as well and are less susceptible to
> such problems:
> (replace-regexp-in-string "[\t\n\r\f]"
> (lambda (s)
> (or (cdr (assoc s '(("\t" . "Î")
> ("\n" . "ñ")
> ("\r" . "®"))))
> "£"))
> regexp)
That works 100%. Even in Emacs 23 ;-). Thanks!
> Stefan
--
Alan Mackenzie (Nuremberg, Germany).
prev parent reply other threads:[~2009-11-19 17:08 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-18 19:12 [acm@muc.de: Re: Inadequate documentation of silly characters on screen.] Alan Mackenzie
2009-11-19 1:27 ` Fwd: Re: Inadequate documentation of silly characters on screen Stefan Monnier
2009-11-19 8:20 ` Alan Mackenzie
2009-11-19 8:50 ` Miles Bader
2009-11-19 10:16 ` Fwd: " Andreas Schwab
2009-11-19 12:21 ` Alan Mackenzie
2009-11-19 13:21 ` Jason Rumney
2009-11-19 13:35 ` Stefan Monnier
2009-11-19 14:18 ` Alan Mackenzie
2009-11-19 14:58 ` Jason Rumney
2009-11-19 15:42 ` Alan Mackenzie
2009-11-19 19:39 ` Eli Zaretskii
2009-11-19 15:30 ` Stefan Monnier
2009-11-19 15:58 ` Alan Mackenzie
2009-11-19 16:06 ` Andreas Schwab
2009-11-19 16:47 ` Aidan Kehoe
2009-11-19 17:29 ` Alan Mackenzie
2009-11-19 18:21 ` Aidan Kehoe
2009-11-20 2:43 ` Stephen J. Turnbull
2009-11-19 19:45 ` Eli Zaretskii
2009-11-19 20:07 ` Eli Zaretskii
2009-11-19 19:55 ` Stefan Monnier
2009-11-20 3:13 ` Stephen J. Turnbull
2009-11-19 16:55 ` David Kastrup
2009-11-19 18:08 ` Alan Mackenzie
2009-11-19 19:25 ` Davis Herring
2009-11-19 21:25 ` Alan Mackenzie
2009-11-19 22:31 ` David Kastrup
2009-11-21 22:52 ` Richard Stallman
2009-11-23 2:08 ` Displaying bytes (was: Inadequate documentation of silly characters on screen.) Stefan Monnier
2009-11-23 20:38 ` Richard Stallman
2009-11-23 21:34 ` Per Starbäck
2009-11-24 22:47 ` Richard Stallman
2009-11-25 1:33 ` Kenichi Handa
2009-11-25 2:29 ` Displaying bytes (was: Inadequate documentation of silly Stefan Monnier
2009-11-25 2:50 ` Lennart Borgman
2009-11-25 6:25 ` Stephen J. Turnbull
2009-11-25 5:40 ` Displaying bytes (was: Inadequate documentation of silly characters on screen.) Ulrich Mueller
2009-11-26 22:59 ` Displaying bytes Reiner Steib
2009-11-27 0:16 ` Ulrich Mueller
2009-11-27 1:41 ` Stefan Monnier
2009-11-27 4:14 ` Stephen J. Turnbull
2009-11-25 5:59 ` Displaying bytes (was: Inadequate documentation of silly characters on screen.) Stephen J. Turnbull
2009-11-25 8:16 ` Kenichi Handa
2009-11-29 16:01 ` Richard Stallman
2009-11-29 16:31 ` Displaying bytes (was: Inadequate documentation of silly Stefan Monnier
2009-11-29 22:01 ` Juri Linkov
2009-11-30 6:05 ` tomas
2009-11-30 12:09 ` Andreas Schwab
2009-11-30 12:39 ` tomas
2009-11-29 22:19 ` Displaying bytes (was: Inadequate documentation of silly characters on screen.) Kim F. Storm
2009-11-30 1:42 ` Stephen J. Turnbull
2009-11-24 1:28 ` Displaying bytes Stefan Monnier
2009-11-24 22:47 ` Richard Stallman
2009-11-25 2:18 ` Stefan Monnier
2009-11-26 6:24 ` Richard Stallman
2009-11-26 8:59 ` David Kastrup
2009-11-26 14:57 ` Stefan Monnier
2009-11-26 16:28 ` Lennart Borgman
2009-11-27 6:36 ` Richard Stallman
2009-11-24 22:47 ` Richard Stallman
2009-11-20 8:48 ` Fwd: Re: Inadequate documentation of silly characters on screen Eli Zaretskii
2009-11-19 19:52 ` Eli Zaretskii
2009-11-19 20:53 ` Alan Mackenzie
2009-11-19 22:16 ` David Kastrup
2009-11-20 8:55 ` Eli Zaretskii
2009-11-19 20:05 ` Stefan Monnier
2009-11-19 21:27 ` Alan Mackenzie
2009-11-19 19:43 ` Eli Zaretskii
2009-11-19 21:57 ` Alan Mackenzie
2009-11-19 23:10 ` Stefan Monnier
2009-11-19 20:02 ` Stefan Monnier
2009-11-19 14:08 ` Stefan Monnier
2009-11-19 14:50 ` Jason Rumney
2009-11-19 15:27 ` Stefan Monnier
2009-11-19 23:12 ` Miles Bader
2009-11-20 2:16 ` Stefan Monnier
2009-11-20 3:37 ` Stephen J. Turnbull
2009-11-20 4:30 ` Stefan Monnier
2009-11-20 7:18 ` Stephen J. Turnbull
2009-11-20 14:16 ` Stefan Monnier
2009-11-21 4:13 ` Stephen J. Turnbull
2009-11-21 5:24 ` Stefan Monnier
2009-11-21 6:42 ` Stephen J. Turnbull
2009-11-21 6:49 ` Stefan Monnier
2009-11-21 7:27 ` Stephen J. Turnbull
2009-11-23 1:58 ` Stefan Monnier
2009-11-21 12:33 ` David Kastrup
2009-11-21 13:55 ` Stephen J. Turnbull
2009-11-21 14:36 ` David Kastrup
2009-11-21 17:53 ` Stephen J. Turnbull
2009-11-21 23:30 ` David Kastrup
2009-11-22 1:27 ` Sebastian Rose
2009-11-22 8:06 ` David Kastrup
2009-11-22 23:52 ` Sebastian Rose
2009-11-19 17:08 ` Alan Mackenzie [this message]
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