From: Kenichi Handa <handa@m17n.org>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: emacs-devel@gnu.org
Subject: Re: (aset UNIBYTE-STRING MULTIBYTE-CHAR)
Date: Fri, 15 Feb 2008 10:39:01 +0900 [thread overview]
Message-ID: <E1JPpXZ-0006Ii-JY@etlken.m17n.org> (raw)
In-Reply-To: <jwvwsp8vpx8.fsf-monnier+emacs@gnu.org> (message from Stefan Monnier on Wed, 13 Feb 2008 10:33:23 -0500)
In article <jwvwsp8vpx8.fsf-monnier+emacs@gnu.org>, Stefan Monnier <monnier@iro.umontreal.ca> writes:
> > Something like this code:
> > (setq result (cons
> > (let ((str (make-string 1 0)))
> > (aset str 0 (make-char 'japanese-jisx0208 ku ten))
> That's truly horrendous code. I see no reason to support it.
> > although it's easy to fix it...
> Not only it's easy but the result is more efficient/legible/maintainable.
Even if the code is very bad, it worked in Emacs 22. If
it doesn't work in Emacs 23, it's a regression.
>>> aset on strings is fundamentally problematic, so anything that restricts
>>> it further is good in my book (my own local Emacs disallows them
>>> plainly, and I rarely bump into code that needs it).
> > What is the fundamental problem?
> The one you're bumping into: multibyte strings are not arrays and
> treating them like ones asks for trouble: the performance is not the one
> expected, the implementation is complex and ugly, ...
The problem here is that (make-string 1 ?a) is a unibyte
string, but "a" generated by buffer-substring on a multibyte
buffer is a multibyte string. The result of concatinating
them is also multibyte. So, the multibyteness of strings is
difficult of expect. If we are going to inhibit aset on
multibyte strings, I think we should inhibit aset on any
strings to avoid a further confusion.
> When weighed against the *very* rare cases where aset is used (let
> alone the even more rare cases where aset is actually useful and
> convenient), the choice is trivial (for me anyway).
Then, shouldn't we start the experiment of inhibitting aset
on strings just now?
---
Kenichi Handa
handa@ni.aist.go.jp
next prev parent reply other threads:[~2008-02-15 1:39 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-13 2:36 (aset UNIBYTE-STRING MULTIBYTE-CHAR) Kenichi Handa
2008-02-13 2:49 ` Stefan Monnier
2008-02-13 3:48 ` Kenichi Handa
2008-02-13 15:33 ` Stefan Monnier
2008-02-13 18:06 ` Stephen J. Turnbull
2008-02-13 19:33 ` Stefan Monnier
2008-02-13 22:49 ` Miles Bader
2008-02-14 1:11 ` Stephen J. Turnbull
2008-02-14 1:17 ` Miles Bader
2008-02-14 1:40 ` Stefan Monnier
2008-02-14 1:49 ` Miles Bader
2008-02-14 18:10 ` Richard Stallman
2008-02-14 22:40 ` David Kastrup
2008-02-15 1:08 ` Stephen J. Turnbull
2008-02-15 1:17 ` Miles Bader
2008-02-15 7:27 ` David Kastrup
2008-02-15 12:58 ` Richard Stallman
2008-02-14 23:37 ` Leo
2008-02-15 12:59 ` Richard Stallman
2008-02-14 4:20 ` Stephen J. Turnbull
2008-02-14 4:42 ` Richard Stallman
2008-02-15 1:39 ` Kenichi Handa [this message]
2008-02-15 4:27 ` Stefan Monnier
2008-02-15 8:42 ` Eli Zaretskii
2008-02-15 8:53 ` Miles Bader
2008-02-16 12:55 ` Eli Zaretskii
2008-02-16 5:53 ` Richard Stallman
2008-02-16 14:33 ` Stefan Monnier
2008-02-17 20:29 ` Richard Stallman
2008-02-18 1:15 ` Stefan Monnier
2008-02-18 4:00 ` Kenichi Handa
2008-02-18 17:31 ` Richard Stallman
2008-02-13 22:01 ` Richard Stallman
2008-02-13 23:13 ` Miles Bader
-- strict thread matches above, loose matches on Subject: below --
2008-04-15 7:11 Kenichi Handa
2008-04-15 15:52 ` Stefan Monnier
2008-04-17 1:13 ` Kenichi Handa
2008-05-07 19:31 Harald Hanche-Olsen
2008-05-14 6:54 ` Harald Hanche-Olsen
2008-05-14 12:22 ` Stefan Monnier
2008-05-14 12:50 ` Harald Hanche-Olsen
2008-05-15 1:18 ` Stefan Monnier
2008-05-15 6:11 ` Harald Hanche-Olsen
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