From: Eli Zaretskii <eliz@gnu.org>
To: Kenichi Handa <handa@m17n.org>
Cc: emacs-devel@gnu.org
Subject: Re: Emacs 23 character code space
Date: Sat, 22 Nov 2008 18:28:13 +0200 [thread overview]
Message-ID: <uk5aviv36.fsf@gnu.org> (raw)
In-Reply-To: <E1Kwyo4-0007Vt-Ai@etlken.m17n.org>
> From: Kenichi Handa <handa@m17n.org>
> CC: eliz@gnu.org, emacs-devel@gnu.org
> Date: Mon, 03 Nov 2008 21:45:20 +0900
>
> I tried to rewrite nonascii.texi to clear the things. I
> finished upto the "Character Code" section as attached.
> What do you think about it?
Thanks!
I have a few questions:
Emacs can convert unibyte text to multibyte; it can also convert
multibyte text to unibyte provided that the multibyte text contains
only @acronym{ASCII} and 8-bit characters.
What exactly is meant here by ``8-bit characters''? Do you mean
eight-bit raw bytes, or do you mean Unicode characters whose
codepoints are below 256?
Converting unibyte text to multibyte text leaves @acronym{ASCII} characters
unchanged, and converts 8-bit characters (codes 128 through 159) to
the corresponding representation for multibyte text.
Again, by ``8-bit characters'' you mean raw 8-bit bytes here, right?
@defun string-to-multibyte string
This function returns a multibyte string containing the same sequence
of characters as @var{string}. If @var{string} is a multibyte string,
it is returned unchanged.
@end defun
I'm not sure I understand the effect of this function. Does it decode
its argument, converting each byte to the corresponding internal
representation of the encoded single-byte character? I think this is
not what it does, but then what does it do?
@defun string-to-unibyte string
This function returns a unibyte string containing the same sequence of
characters as @var{string}. It signals an error if @var{string}
contains a non-@acronym{ASCII} character. If @var{string} is a
unibyte string, it is returned unchanged.
@end defun
Since this function handles any non-ASCII characters lossily, when
would it be useful?
@defun multibyte-char-to-unibyte char
This convert the multibyte character @var{char} to a unibyte
character. If @var{char} is a non-@acronym{ASCII} character, the
value is -1.
@end defun
@defun unibyte-char-to-multibyte char
This convert the unibyte character @var{char} to a multibyte
character.
@end defun
Again, when are these functions useful?
next prev parent reply other threads:[~2008-11-22 16:28 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-01 14:20 Emacs 23 character code space Eli Zaretskii
2008-11-01 16:46 ` Eli Zaretskii
2008-11-03 1:34 ` Kenichi Handa
2008-11-03 12:45 ` Kenichi Handa
2008-11-03 20:13 ` Eli Zaretskii
2008-11-04 7:35 ` Kenichi Handa
2008-11-04 20:19 ` Eli Zaretskii
2008-11-05 12:27 ` Kenichi Handa
2008-11-05 18:23 ` Eli Zaretskii
2008-11-22 18:25 ` Eli Zaretskii
2008-11-26 1:41 ` Kenichi Handa
2008-11-26 4:13 ` Eli Zaretskii
2008-11-26 4:24 ` Kenichi Handa
2008-11-26 4:58 ` Kenichi Handa
2008-11-26 20:26 ` Eli Zaretskii
2008-11-26 22:52 ` Juanma Barranquero
2008-11-27 1:10 ` Stephen J. Turnbull
2008-11-27 1:35 ` Kenichi Handa
2008-11-26 20:18 ` Eli Zaretskii
2008-11-27 1:29 ` Kenichi Handa
2008-11-29 17:12 ` Eli Zaretskii
2008-12-02 5:40 ` Kenichi Handa
2008-11-28 13:19 ` Eli Zaretskii
2008-12-02 5:44 ` Kenichi Handa
2008-12-02 19:40 ` Eli Zaretskii
2008-11-29 12:01 ` Eli Zaretskii
2008-11-22 16:28 ` Eli Zaretskii [this message]
2008-11-23 4:16 ` Stefan Monnier
2008-11-23 11:22 ` Eli Zaretskii
2008-11-26 1:51 ` Kenichi Handa
2008-11-23 8:29 ` Ulrich Mueller
2008-11-23 11:11 ` Eli Zaretskii
2008-11-23 11:55 ` Ulrich Mueller
2008-11-24 3:06 ` Stefan Monnier
2008-11-26 1:31 ` Kenichi Handa
2008-11-22 17:03 ` New function: what-file-line, used when writing gdb script richardeng
2008-11-07 7:21 ` Emacs 23 character code space Kenichi Handa
2008-11-07 10:27 ` Eli Zaretskii
2008-11-07 11:52 ` Kenichi Handa
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