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* basic.texi (Inserting Text): Document ucs-insert.
* mule.texi (International Chars): Define "multibyte". Note that internal representation is unicode-based. Simplify definition of raw bytes. Mention ucs-insert. (Enabling Multibyte): Remove obsolete discussion. Copyedits. (Language Environments): Add language environments new to Emacs 23. (Multibyte Conversion): Node deleted. (Coding Systems): Remove obsolete unify-8859-on-decoding-mode. Don't mention obsolete emacs-mule coding system. (Output Coding): Copyedits. * emacs.texi (Top): Update node listing.
This commit is contained in:
Chong Yidong
parent
5996e1b74c
commit
ad36c4224c
@ -1,3 +1,19 @@
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2009-05-06 Chong Yidong <cyd@stupidchicken.com>
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* basic.texi (Inserting Text): Document ucs-insert.
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* mule.texi (International Chars): Define "multibyte". Note that
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internal representation is unicode-based. Simplify definition of raw
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bytes. Mention ucs-insert.
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(Enabling Multibyte): Remove obsolete discussion. Copyedits.
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(Language Environments): Add language environments new to Emacs 23.
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(Multibyte Conversion): Node deleted.
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(Coding Systems): Remove obsolete unify-8859-on-decoding-mode. Don't
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mention obsolete emacs-mule coding system.
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(Output Coding): Copyedits.
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* emacs.texi (Top): Update node listing.
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2009-05-05 Per Starbäck <per@starback.se> (tiny change)
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* trouble.texi (Lossage): Use new binding of view-emacs-problems.
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@ -64,9 +64,11 @@ key; other keys act as editing commands and do not insert themselves.
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For instance, @kbd{DEL} runs the command @code{delete-backward-char}
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by default (some modes bind it to a different command); it does not
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insert a literal @samp{DEL} character (@acronym{ASCII} character code
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127). To insert a non-graphic character, first @dfn{quote} it by
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typing @kbd{C-q} (@code{quoted-insert}). There are two ways to use
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@kbd{C-q}:
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127).
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To insert a non-graphic character, or a character that your keyboard
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does not support, first @dfn{quote} it by typing @kbd{C-q}
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(@code{quoted-insert}). There are two ways to use @kbd{C-q}:
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@itemize @bullet
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@item
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@ -87,32 +89,24 @@ Overwrite mode, to give you a convenient way to insert a digit instead
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of overwriting with it.
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@end itemize
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@cindex 8-bit character codes
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@noindent
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If you specify a code in the octal range 0200 through 0377, @kbd{C-q}
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assumes that you intend to use some ISO 8859-@var{n} character set,
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and converts the specified code to the corresponding Emacs character
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code. Your choice of language environment determines which of the ISO
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8859 character sets to use (@pxref{Language Environments}). This
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feature is disabled if multibyte characters are disabled
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(@pxref{Enabling Multibyte}).
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@vindex read-quoted-char-radix
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@noindent
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To use decimal or hexadecimal instead of octal, set the variable
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@code{read-quoted-char-radix} to 10 or 16. If the radix is greater than
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10, some letters starting with @kbd{a} serve as part of a character
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code, just like digits.
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@code{read-quoted-char-radix} to 10 or 16. If the radix is greater
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than 10, some letters starting with @kbd{a} serve as part of a
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character code, just like digits.
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A numeric argument tells @kbd{C-q} how many copies of the quoted
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A numeric argument tells @kbd{C-q} how many copies of the quoted
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character to insert (@pxref{Arguments}).
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@findex newline
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@findex self-insert
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Customization information: @key{DEL} in most modes runs the command
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@code{delete-backward-char}; @key{RET} runs the command
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@code{newline}, and self-inserting printing characters run the command
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@code{self-insert}, which inserts whatever character you typed. Some
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major modes rebind @key{DEL} to other commands.
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@findex ucs-insert
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@cindex Unicode
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Instead of @kbd{C-q}, you can use @kbd{C-x 8 @key{RET}}
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(@code{ucs-insert}) to insert a character based on its Unicode name or
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code-point. This commands prompts for a character to insert, using
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the minibuffer; you can specify the character using either (i) the
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character's name in the Unicode standard, or (ii) the character's
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code-point in the Unicode standard.
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@node Moving Point
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@section Changing the Location of Point
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@ -507,7 +507,6 @@ International Character Set Support
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* Language Environments:: Setting things up for the language you use.
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* Input Methods:: Entering text characters not on your keyboard.
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* Select Input Method:: Specifying your choice of input methods.
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* Multibyte Conversion:: How single-byte characters convert to multibyte.
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* Coding Systems:: Character set conversion when you read and
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write files, and so on.
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* Recognize Coding:: How Emacs figures out which conversion to use.
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@ -89,7 +89,6 @@ to make sure Emacs interprets keyboard input correctly; see
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* Language Environments:: Setting things up for the language you use.
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* Input Methods:: Entering text characters not on your keyboard.
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* Select Input Method:: Specifying your choice of input methods.
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* Multibyte Conversion:: How single-byte characters convert to multibyte.
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* Coding Systems:: Character set conversion when you read and
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write files, and so on.
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* Recognize Coding:: How Emacs figures out which conversion to use.
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@ -115,14 +114,17 @@ to make sure Emacs interprets keyboard input correctly; see
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The users of international character sets and scripts have
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established many more-or-less standard coding systems for storing
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files. Emacs internally uses a single multibyte character encoding,
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so that it can intermix characters from all these scripts in a single
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buffer or string. This encoding represents each non-@acronym{ASCII}
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character as a sequence of bytes in the range 0200 through 0377.
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Emacs translates between the multibyte character encoding and various
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other coding systems when reading and writing files, when exchanging
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data with subprocesses, and (in some cases) in the @kbd{C-q} command
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(@pxref{Multibyte Conversion}).
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files. These coding systems are typically @dfn{multibyte}, meaning
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that sequences of two or more bytes are used to represent individual
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non-@acronym{ASCII} characters.
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@cindex Unicode
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Internally, Emacs uses its own multibyte character encoding, which
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is a superset of the @dfn{Unicode} standard. This internal encoding
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allows characters from almost every known script to be intermixed in a
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single buffer or string. Emacs translates between the multibyte
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character encoding and various other coding systems when reading and
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writing files, and when exchanging data with subprocesses.
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@kindex C-h h
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@findex view-hello-file
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@ -134,10 +136,14 @@ This illustrates various scripts. If some characters can't be
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displayed on your terminal, they appear as @samp{?} or as hollow boxes
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(@pxref{Undisplayable Characters}).
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Keyboards, even in the countries where these character sets are used,
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generally don't have keys for all the characters in them. So Emacs
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supports various @dfn{input methods}, typically one for each script or
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language, to make it convenient to type them.
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Keyboards, even in the countries where these character sets are
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used, generally don't have keys for all the characters in them. You
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can insert characters that your keyboard does not support, using
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@kbd{C-q} (@code{quoted-insert}) or @kbd{C-x 8 @key{RET}}
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(@code{ucs-insert}). @xref{Inserting Text}. Emacs also supports
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various @dfn{input methods}, typically one for each script or
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language, which make it easier to type characters in the script.
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@xref{Input Methods}.
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@kindex C-x RET
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The prefix key @kbd{C-x @key{RET}} is used for commands that pertain
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@ -165,12 +171,12 @@ system encodes the character safely and with a single byte
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(@pxref{Coding Systems}). If the character's encoding is longer than
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one byte, Emacs shows @samp{file ...}.
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However, if the character displayed is in the range 0200 through
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0377 octal, it may actually stand for an invalid UTF-8 byte read from
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a file. In Emacs, that byte is represented as a sequence of 8-bit
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characters, but all of them together display as the original invalid
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byte, in octal code. In this case, @kbd{C-x =} shows @samp{part of
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display ...} instead of @samp{file}.
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As a special case, if the character lies in the range 128 (0200
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octal) through 159 (0237 octal), it stands for a ``raw'' byte that
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does not correspond to any specific displayable character. Such a
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``character'' lies within the @code{eight-bit-control} character set,
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and is displayed as an escaped octal character code. In this case,
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@kbd{C-x =} shows @samp{part of display ...} instead of @samp{file}.
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@cindex character set of character at point
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@cindex font of character at point
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@ -235,74 +241,62 @@ There are text properties here:
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@node Enabling Multibyte
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@section Enabling Multibyte Characters
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By default, Emacs starts in multibyte mode, because that allows you to
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use all the supported languages and scripts without limitations.
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By default, Emacs starts in multibyte mode: it stores the contents
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of buffers and strings using an internal encoding that represents
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non-@acronym{ASCII} characters using multi-byte sequences. Multibyte
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mode allows you to use all the supported languages and scripts without
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limitations.
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@cindex turn multibyte support on or off
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You can enable or disable multibyte character support, either for
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Emacs as a whole, or for a single buffer. When multibyte characters
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are disabled in a buffer, we call that @dfn{unibyte mode}. Then each
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byte in that buffer represents a character, even codes 0200 through
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0377.
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The old features for supporting the European character sets, ISO
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Latin-1 and ISO Latin-2, work in unibyte mode as they did in Emacs 19
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and also work for the other ISO 8859 character sets. However, there
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is no need to turn off multibyte character support to use ISO Latin;
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the Emacs multibyte character set includes all the characters in these
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character sets, and Emacs can translate automatically to and from the
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ISO codes.
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Under very special circumstances, you may want to disable multibyte
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character support, either for Emacs as a whole, or for a single
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buffer. When multibyte characters are disabled in a buffer, we call
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that @dfn{unibyte mode}. In unibyte mode, each character in the
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buffer has a character code ranging from 0 through 255 (0377 octal); 0
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through 127 (0177 octal) represent @acronym{ASCII} characters, and 128
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(0200 octal) through 255 (0377 octal) represent non-@acronym{ASCII}
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characters.
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To edit a particular file in unibyte representation, visit it using
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@code{find-file-literally}. @xref{Visiting}. To convert a buffer in
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multibyte representation into a single-byte representation of the same
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characters, the easiest way is to save the contents in a file, kill the
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buffer, and find the file again with @code{find-file-literally}. You
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can also use @kbd{C-x @key{RET} c}
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(@code{universal-coding-system-argument}) and specify @samp{raw-text} as
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the coding system with which to find or save a file. @xref{Text
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Coding}. Finding a file as @samp{raw-text} doesn't disable format
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conversion, uncompression and auto mode selection as
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@code{find-file-literally} does.
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@code{find-file-literally}. @xref{Visiting}. You can convert a
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multibyte buffer to unibyte by saving it to a file, killing the
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buffer, and visiting the file again with @code{find-file-literally}.
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Alternatively, you can use @kbd{C-x @key{RET} c}
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(@code{universal-coding-system-argument}) and specify @samp{raw-text}
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as the coding system with which to visit or save a file. @xref{Text
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Coding}. Unlike @code{find-file-literally}, finding a file as
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@samp{raw-text} doesn't disable format conversion, uncompression, or
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auto mode selection.
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@vindex enable-multibyte-characters
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@vindex default-enable-multibyte-characters
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@cindex environment variables, and non-@acronym{ASCII} characters
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To turn off multibyte character support by default, start Emacs with
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the @samp{--unibyte} option (@pxref{Initial Options}), or set the
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environment variable @env{EMACS_UNIBYTE}. You can also customize
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@code{enable-multibyte-characters} or, equivalently, directly set the
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variable @code{default-enable-multibyte-characters} to @code{nil} in
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your init file to have basically the same effect as @samp{--unibyte}.
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@findex toggle-enable-multibyte-characters
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To convert a unibyte session to a multibyte session, set
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@code{default-enable-multibyte-characters} to @code{t}. Buffers which
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were created in the unibyte session before you turn on multibyte support
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will stay unibyte. You can turn on multibyte support in a specific
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buffer by invoking the command @code{toggle-enable-multibyte-characters}
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in that buffer.
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With @samp{--unibyte}, multibyte strings are not created during
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initialization from the values of environment variables,
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@file{/etc/passwd} entries etc., even if those contain
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non-@acronym{ASCII} characters.
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@cindex Lisp files, and multibyte operation
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@cindex multibyte operation, and Lisp files
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@cindex unibyte operation, and Lisp files
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@cindex init file, and non-@acronym{ASCII} characters
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@cindex environment variables, and non-@acronym{ASCII} characters
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With @samp{--unibyte}, multibyte strings are not created during
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initialization from the values of environment variables,
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@file{/etc/passwd} entries etc.@: that contain non-@acronym{ASCII} 8-bit
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characters.
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Emacs normally loads Lisp files as multibyte, regardless of whether
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you used @samp{--unibyte}. This includes the Emacs initialization file,
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@file{.emacs}, and the initialization files of Emacs packages such as
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Gnus. However, you can specify unibyte loading for a particular Lisp
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file, by putting @w{@samp{-*-unibyte: t;-*-}} in a comment on the first
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line (@pxref{File Variables}). Then that file is always loaded as
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unibyte text, even if you did not start Emacs with @samp{--unibyte}.
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The motivation for these conventions is that it is more reliable to
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always load any particular Lisp file in the same way. However, you can
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load a Lisp file as unibyte, on any one occasion, by typing @kbd{C-x
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@key{RET} c raw-text @key{RET}} immediately before loading it.
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you used @samp{--unibyte}. This includes the Emacs initialization
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file, @file{.emacs}, and the initialization files of Emacs packages
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such as Gnus. However, you can specify unibyte loading for a
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particular Lisp file, by putting @w{@samp{-*-unibyte: t;-*-}} in a
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comment on the first line (@pxref{File Variables}). Then that file is
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always loaded as unibyte text. The motivation for these conventions
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is that it is more reliable to always load any particular Lisp file in
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the same way. However, you can load a Lisp file as unibyte, on any
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one occasion, by typing @kbd{C-x @key{RET} c raw-text @key{RET}}
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immediately before loading it.
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The mode line indicates whether multibyte character support is
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enabled in the current buffer. If it is, there are two or more
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@ -312,6 +306,14 @@ convention (colon, backslash, etc.). When multibyte characters
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are not enabled, nothing precedes the colon except a single dash.
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@xref{Mode Line}, for more details about this.
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@findex toggle-enable-multibyte-characters
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To convert a unibyte session to a multibyte session, set
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@code{default-enable-multibyte-characters} to @code{t}. Buffers which
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were created in the unibyte session before you turn on multibyte
|
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support will stay unibyte. You can turn on multibyte support in a
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specific buffer by invoking the command
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@code{toggle-enable-multibyte-characters} in that buffer.
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@node Language Environments
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@section Language Environments
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@cindex language environments
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@ -319,43 +321,41 @@ are not enabled, nothing precedes the colon except a single dash.
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All supported character sets are supported in Emacs buffers whenever
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multibyte characters are enabled; there is no need to select a
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particular language in order to display its characters in an Emacs
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buffer. However, it is important to select a @dfn{language environment}
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in order to set various defaults. The language environment really
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represents a choice of preferred script (more or less) rather than a
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choice of language.
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buffer. However, it is important to select a @dfn{language
|
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environment} in order to set various defaults. Roughly speaking, the
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language environment represents a choice of preferred script rather
|
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than a choice of language.
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The language environment controls which coding systems to recognize
|
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when reading text (@pxref{Recognize Coding}). This applies to files,
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incoming mail, netnews, and any other text you read into Emacs. It may
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also specify the default coding system to use when you create a file.
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Each language environment also specifies a default input method.
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incoming mail, and any other text you read into Emacs. It may also
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specify the default coding system to use when you create a file. Each
|
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language environment also specifies a default input method.
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@findex set-language-environment
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@vindex current-language-environment
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To select a language environment, you can customize the variable
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To select a language environment, customize the variable
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@code{current-language-environment} or use the command @kbd{M-x
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set-language-environment}. It makes no difference which buffer is
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current when you use this command, because the effects apply globally to
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the Emacs session. The supported language environments include:
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current when you use this command, because the effects apply globally
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to the Emacs session. The supported language environments include:
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|
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@cindex Euro sign
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@cindex UTF-8
|
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@quotation
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ASCII, Belarusian, Brazilian Portuguese, Bulgarian, Chinese-BIG5,
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Chinese-CNS, Chinese-EUC-TW, Chinese-GB, Croatian, Cyrillic-ALT,
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Cyrillic-ISO, Cyrillic-KOI8, Czech, Devanagari, Dutch, English,
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Esperanto, Ethiopic, French, Georgian, German, Greek, Hebrew, IPA,
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Italian, Japanese, Kannada, Korean, Lao, Latin-1, Latin-2, Latin-3,
|
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Latin-4, Latin-5, Latin-6, Latin-7, Latin-8 (Celtic), Latin-9 (updated
|
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Latin-1 with the Euro sign), Latvian, Lithuanian, Malayalam, Polish,
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Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, Tajik, Tamil,
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Thai, Tibetan, Turkish, UTF-8 (for a setup which prefers Unicode
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characters and files encoded in UTF-8), Ukrainian, Vietnamese, Welsh,
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and Windows-1255 (for a setup which prefers Cyrillic characters and
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files encoded in Windows-1255).
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@tex
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\hbadness=10000\par % just avoid underfull hbox warning
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@end tex
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ASCII, Belarusian, Bengali, Brazilian Portuguese, Bulgarian,
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Chinese-BIG5, Chinese-CNS, Chinese-EUC-TW, Chinese-GB, Chinese-GBK,
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Chinese-GB18030, Croatian, Cyrillic-ALT, Cyrillic-ISO, Cyrillic-KOI8,
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Czech, Devanagari, Dutch, English, Esperanto, Ethiopic, French,
|
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Georgian, German, Greek, Gujarati, Hebrew, IPA, Italian, Japanese,
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Kannada, Khmer, Korean, Lao, Latin-1, Latin-2, Latin-3, Latin-4,
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Latin-5, Latin-6, Latin-7, Latin-8 (Celtic), Latin-9 (updated Latin-1
|
||||
with the Euro sign), Latvian, Lithuanian, Malayalam, Oriya, Polish,
|
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Punjabi, Romanian, Russian, Sinhala, Slovak, Slovenian, Spanish,
|
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Swedish, TaiViet, Tajik, Tamil, Telugu, Thai, Tibetan, Turkish, UTF-8
|
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(for a setup which prefers Unicode characters and files encoded in
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UTF-8), Ukrainian, Vietnamese, Welsh, and Windows-1255 (for a setup
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which prefers Cyrillic characters and files encoded in Windows-1255).
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@end quotation
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|
||||
@cindex fonts for various scripts
|
||||
@ -657,34 +657,6 @@ character.
|
||||
list-input-methods}. The list gives information about each input
|
||||
method, including the string that stands for it in the mode line.
|
||||
|
||||
@node Multibyte Conversion
|
||||
@section Unibyte and Multibyte Non-@acronym{ASCII} characters
|
||||
|
||||
When multibyte characters are enabled, character codes 0240 (octal)
|
||||
through 0377 (octal) are not really legitimate in the buffer. The valid
|
||||
non-@acronym{ASCII} printing characters have codes that start from 0400.
|
||||
|
||||
If you type a self-inserting character in the range 0240 through
|
||||
0377, or if you use @kbd{C-q} to insert one, Emacs assumes you
|
||||
intended to use one of the ISO Latin-@var{n} character sets, and
|
||||
converts it to the Emacs code representing that Latin-@var{n}
|
||||
character. You select @emph{which} ISO Latin character set to use
|
||||
through your choice of language environment
|
||||
@iftex
|
||||
(see above).
|
||||
@end iftex
|
||||
@ifnottex
|
||||
(@pxref{Language Environments}).
|
||||
@end ifnottex
|
||||
If you do not specify a choice, the default is Latin-1.
|
||||
|
||||
If you insert a character in the range 0200 through 0237, which
|
||||
forms the @code{eight-bit-control} character set, it is inserted
|
||||
literally. You should normally avoid doing this since buffers
|
||||
containing such characters have to be written out in either the
|
||||
@code{emacs-mule} or @code{raw-text} coding system, which is usually
|
||||
not what you want.
|
||||
|
||||
@node Coding Systems
|
||||
@section Coding Systems
|
||||
@cindex coding systems
|
||||
@ -698,11 +670,11 @@ possible in reading or writing files, in sending or receiving from the
|
||||
terminal, and in exchanging data with subprocesses.
|
||||
|
||||
Emacs assigns a name to each coding system. Most coding systems are
|
||||
used for one language, and the name of the coding system starts with the
|
||||
language name. Some coding systems are used for several languages;
|
||||
their names usually start with @samp{iso}. There are also special
|
||||
coding systems @code{no-conversion}, @code{raw-text} and
|
||||
@code{emacs-mule} which do not convert printing characters at all.
|
||||
used for one language, and the name of the coding system starts with
|
||||
the language name. Some coding systems are used for several
|
||||
languages; their names usually start with @samp{iso}. There are also
|
||||
special coding systems, such as @code{no-conversion}, @code{raw-text},
|
||||
and @code{emacs-internal}.
|
||||
|
||||
@cindex international files from DOS/Windows systems
|
||||
A special class of coding systems, collectively known as
|
||||
@ -814,37 +786,21 @@ the @kbd{M-x find-file-literally} command. This uses
|
||||
@code{no-conversion}, and also suppresses other Emacs features that
|
||||
might convert the file contents before you see them. @xref{Visiting}.
|
||||
|
||||
The coding system @code{emacs-mule} means that the file contains
|
||||
non-@acronym{ASCII} characters stored with the internal Emacs encoding. It
|
||||
handles end-of-line conversion based on the data encountered, and has
|
||||
the usual three variants to specify the kind of end-of-line conversion.
|
||||
|
||||
@findex unify-8859-on-decoding-mode
|
||||
@anchor{Character Translation}
|
||||
The @dfn{character translation} feature can modify the effect of
|
||||
various coding systems, by changing the internal Emacs codes that
|
||||
decoding produces. For instance, the command
|
||||
@code{unify-8859-on-decoding-mode} enables a mode that ``unifies'' the
|
||||
Latin alphabets when decoding text. This works by converting all
|
||||
non-@acronym{ASCII} Latin-@var{n} characters to either Latin-1 or
|
||||
Unicode characters. This way it is easier to use various
|
||||
Latin-@var{n} alphabets together. (In a future Emacs version we hope
|
||||
to move towards full Unicode support and complete unification of
|
||||
character sets.)
|
||||
|
||||
@vindex enable-character-translation
|
||||
If you set the variable @code{enable-character-translation} to
|
||||
@code{nil}, that disables all character translation (including
|
||||
@code{unify-8859-on-decoding-mode}).
|
||||
The coding system @code{emacs-internal} (or @code{utf-8-emacs},
|
||||
which is equivalent) means that the file contains non-@acronym{ASCII}
|
||||
characters stored with the internal Emacs encoding. This coding
|
||||
system handles end-of-line conversion based on the data encountered,
|
||||
and has the usual three variants to specify the kind of end-of-line
|
||||
conversion.
|
||||
|
||||
@node Recognize Coding
|
||||
@section Recognizing Coding Systems
|
||||
|
||||
Emacs tries to recognize which coding system to use for a given text
|
||||
as an integral part of reading that text. (This applies to files
|
||||
being read, output from subprocesses, text from X selections, etc.)
|
||||
Emacs can select the right coding system automatically most of the
|
||||
time---once you have specified your preferences.
|
||||
Whenever Emacs reads a given piece of text, it tries to recognize
|
||||
which coding system to use. This applies to files being read, output
|
||||
from subprocesses, text from X selections, etc. Emacs can select the
|
||||
right coding system automatically most of the time---once you have
|
||||
specified your preferences.
|
||||
|
||||
Some coding systems can be recognized or distinguished by which byte
|
||||
sequences appear in the data. However, there are coding systems that
|
||||
@ -948,19 +904,17 @@ pattern, are decoded correctly. One of the builtin
|
||||
@code{auto-coding-functions} detects the encoding for XML files.
|
||||
|
||||
@vindex rmail-decode-mime-charset
|
||||
@vindex rmail-file-coding-system
|
||||
When you get new mail in Rmail, each message is translated
|
||||
automatically from the coding system it is written in, as if it were a
|
||||
separate file. This uses the priority list of coding systems that you
|
||||
have specified. If a MIME message specifies a character set, Rmail
|
||||
obeys that specification, unless @code{rmail-decode-mime-charset} is
|
||||
@code{nil}.
|
||||
|
||||
@vindex rmail-file-coding-system
|
||||
For reading and saving Rmail files themselves, Emacs uses the coding
|
||||
system specified by the variable @code{rmail-file-coding-system}. The
|
||||
default value is @code{nil}, which means that Rmail files are not
|
||||
translated (they are read and written in the Emacs internal character
|
||||
code).
|
||||
@code{nil}. For reading and saving Rmail files themselves, Emacs uses
|
||||
the coding system specified by the variable
|
||||
@code{rmail-file-coding-system}. The default value is @code{nil},
|
||||
which means that Rmail files are not translated (they are read and
|
||||
written in the Emacs internal character code).
|
||||
|
||||
@node Specify Coding
|
||||
@section Specifying a File's Coding System
|
||||
@ -984,13 +938,6 @@ use of the Latin-1 coding system, as well as C mode. When you specify
|
||||
the coding explicitly in the file, that overrides
|
||||
@code{file-coding-system-alist}.
|
||||
|
||||
If you add the character @samp{!} at the end of the coding system
|
||||
name in @code{coding}, it disables any character translation
|
||||
(@pxref{Character Translation}) while decoding the file. This is
|
||||
useful when you need to make sure that the character codes in the
|
||||
Emacs buffer will not vary due to changes in user settings; for
|
||||
instance, for the sake of strings in Emacs Lisp source files.
|
||||
|
||||
@node Output Coding
|
||||
@section Choosing Coding Systems for Output
|
||||
|
||||
@ -1004,22 +951,21 @@ different coding system for further file output from the buffer using
|
||||
|
||||
You can insert any character Emacs supports into any Emacs buffer,
|
||||
but most coding systems can only handle a subset of these characters.
|
||||
Therefore, you can insert characters that cannot be encoded with the
|
||||
coding system that will be used to save the buffer. For example, you
|
||||
could start with an @acronym{ASCII} file and insert a few Latin-1
|
||||
characters into it, or you could edit a text file in Polish encoded in
|
||||
@code{iso-8859-2} and add some Russian words to it. When you save
|
||||
Therefore, it's possible that the characters you insert cannot be
|
||||
encoded with the coding system that will be used to save the buffer.
|
||||
For example, you could visit a text file in Polish, encoded in
|
||||
@code{iso-8859-2}, and add some Russian words to it. When you save
|
||||
that buffer, Emacs cannot use the current value of
|
||||
@code{buffer-file-coding-system}, because the characters you added
|
||||
cannot be encoded by that coding system.
|
||||
|
||||
When that happens, Emacs tries the most-preferred coding system (set
|
||||
by @kbd{M-x prefer-coding-system} or @kbd{M-x
|
||||
set-language-environment}), and if that coding system can safely
|
||||
encode all of the characters in the buffer, Emacs uses it, and stores
|
||||
its value in @code{buffer-file-coding-system}. Otherwise, Emacs
|
||||
displays a list of coding systems suitable for encoding the buffer's
|
||||
contents, and asks you to choose one of those coding systems.
|
||||
set-language-environment}). If that coding system can safely encode
|
||||
all of the characters in the buffer, Emacs uses it, and stores its
|
||||
value in @code{buffer-file-coding-system}. Otherwise, Emacs displays
|
||||
a list of coding systems suitable for encoding the buffer's contents,
|
||||
and asks you to choose one of those coding systems.
|
||||
|
||||
If you insert the unsuitable characters in a mail message, Emacs
|
||||
behaves a bit differently. It additionally checks whether the
|
||||
@ -1248,9 +1194,9 @@ interactively.
|
||||
|
||||
If @code{file-name-coding-system} is @code{nil}, Emacs uses a
|
||||
default coding system determined by the selected language environment.
|
||||
In the default language environment, any non-@acronym{ASCII}
|
||||
characters in file names are not encoded specially; they appear in the
|
||||
file system using the internal Emacs representation.
|
||||
In the default language environment, non-@acronym{ASCII} characters in
|
||||
file names are not encoded specially; they appear in the file system
|
||||
using the internal Emacs representation.
|
||||
|
||||
@strong{Warning:} if you change @code{file-name-coding-system} (or the
|
||||
language environment) in the middle of an Emacs session, problems can
|
||||
@ -1317,7 +1263,7 @@ You can do this by putting
|
||||
@end lisp
|
||||
|
||||
@noindent
|
||||
in your @file{~/.emacs} file.
|
||||
in your init file.
|
||||
|
||||
There is a similarity between using a coding system translation for
|
||||
keyboard input, and using an input method: both define sequences of
|
||||
|
||||
Loading…
Reference in New Issue
Block a user