From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Alan Mackenzie <acm@muc.de>
Cc: Eli Zaretskii <eliz@gnu.org>,
emacs-devel@gnu.org, schwab@linux-m68k.org, jasonr@gnu.org
Subject: Re: Fwd: Re: Inadequate documentation of silly characters on screen.
Date: Thu, 19 Nov 2009 18:10:54 -0500 [thread overview]
Message-ID: <jwvmy2ii0d6.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <20091119215707.GI1314@muc.de> (Alan Mackenzie's message of "Thu, 19 Nov 2009 21:57:07 +0000")
> The abstraction is broken. It is broken because it isn't abstract - its
> users have to think about the way characters are represented. In an
> effective abstraction, a user could just write "ñ" or ?ñ and rely on the
> underlying mechanisms to work.
> Instead of the abstraction "string", we have two grossly inferior
> abstractions, "unibyte string" and "multibyte string".
No: the abstraction "multibyte string" is what you call "a string", it's
absolutely identical. The only problem is that there's one tiny but
significant unsupported spot: when you write a string constant you may
think it's a multibyte string, but Emacs may disagree.
The abstraction "unibyte string" is what you might call "a byte array".
It doesn't have much to do with your idea of a string.
> Please suggest to me the correct elisp to "replace the zeroth character
> of an existing string with Spanish n-twiddle".
For a unibyte string, it's impossible since "Spanish n-twiddle" is not
a byte. For multibyte strings, `aset' will work dandy (tho
inefficiently of course because we're talking about a string, not an
array).
> If this is impossible to write, or it's grossly larger than the buggy
> "(aset nl 0 ?ñ)", that's a demonstration of the breakage.
Except the breakage is elsewhere: you expect `nl' to be a multibyte
string (i.e. "a string" in your mind), whereas Emacs tricked you earlier
and `nl' is really a byte array.
> Why is it necessary to distinguish between 'A' and 65?
It's not usually. Because in almost all coding systems, the character
A is represented by the byte 65.
>> No, I don't agree. If you want to get a human-readable text string,
>> don't use aset; use string operations instead.
> There aren't any.
Of course there are: substring+concat.
> I don't imagine anybody here would hold that the current state of strings
> is ideal. I'm still trying to piece together what the essence of the
> problem is.
The essense is that "\n" is not what you think of as a string: it's
a byte array instead. And Emacs managed to do enough magic to trick you
into thinking until now that it's just like a string.
Stefan
next prev parent reply other threads:[~2009-11-19 23:10 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 [this message]
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 ` Fwd: " Alan Mackenzie
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