From 50148a91b426fb6be9009d968f64b0e6d645e799 Mon Sep 17 00:00:00 2001 From: "Richard M. Stallman" Date: Mon, 3 Jul 2006 15:48:23 +0000 Subject: [PATCH] (Coding Systems): Move char translation stuff here. (Specify Coding, Output Coding): New nodes, out of Recognize Coding. (Recognize Coding): Substantial local rewrites. (International): Update menu. --- man/mule.texi | 144 +++++++++++++++++++++++++++----------------------- 1 file changed, 79 insertions(+), 65 deletions(-) diff --git a/man/mule.texi b/man/mule.texi index 8220a5097d1..15ec08ce9b0 100644 --- a/man/mule.texi +++ b/man/mule.texi @@ -91,6 +91,8 @@ to make sure Emacs interprets keyboard input correctly; see * Coding Systems:: Character set conversion when you read and write files, and so on. * Recognize Coding:: How Emacs figures out which conversion to use. +* Specify Coding:: Specifying a file's coding system explicitly. +* Output Coding:: Choosing coding systems for output. * Text Coding:: Choosing conversion to use for file text. * Communication Coding:: Coding systems for interprocess communication. * File Name Coding:: Coding systems for file @emph{names}. @@ -718,6 +720,23 @@ 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 + 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}). + @node Recognize Coding @section Recognizing Coding Systems @@ -812,26 +831,6 @@ coding system @code{iso-2022-7bit}, and they won't be decoded correctly when you visit those files if you suppress the escape sequence detection. -@vindex coding - You can specify the coding system for a particular file using the -@w{@samp{-*-@dots{}-*-}} construct at the beginning of a file, or a -local variables list at the end (@pxref{File Variables}). You do this -by defining a value for the ``variable'' named @code{coding}. Emacs -does not really have a variable @code{coding}; instead of setting a -variable, this uses the specified coding system for the file. For -example, @samp{-*-mode: C; coding: latin-1;-*-} specifies 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, it disables any character translation while decoding the file. -For instance, it effectively cancels the effect of -@code{unify-8859-on-decoding-mode}. This is useful when you need to -make sure that the character codes in the Emacs buffer will not -according to user settings; for instance, for the sake of strings in -Emacs Lisp source files. - @vindex auto-coding-alist @vindex auto-coding-regexp-alist @vindex auto-coding-functions @@ -848,6 +847,24 @@ RMAIL files, whose names in general don't match any particular pattern, are decoded correctly. One of the builtin @code{auto-coding-functions} detects the encoding for XML files. +@vindex rmail-decode-mime-charset + 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). + +@node Specify Coding +@section Specifying a File's Coding System + If Emacs recognizes the encoding of a file incorrectly, you can reread the file using the correct coding system by typing @kbd{C-x @key{RET} r @var{coding-system} @key{RET}}. To see what coding system @@ -855,33 +872,45 @@ Emacs actually used to decode the file, look at the coding system mnemonic letter near the left edge of the mode line (@pxref{Mode Line}), or type @kbd{C-h C @key{RET}}. -@findex unify-8859-on-decoding-mode - 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 coding + You can specify the coding system for a particular file in the file +itself, using the @w{@samp{-*-@dots{}-*-}} construct at the beginning, +or a local variables list at the end (@pxref{File Variables}). You do +this by defining a value for the ``variable'' named @code{coding}. +Emacs does not really have a variable @code{coding}; instead of +setting a variable, this uses the specified coding system for the +file. For example, @samp{-*-mode: C; coding: latin-1;-*-} specifies +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 while +decoding the file. For instance, it effectively cancels the effect of +@code{unify-8859-on-decoding-mode}. 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 @vindex buffer-file-coding-system Once Emacs has chosen a coding system for a buffer, it stores that -coding system in @code{buffer-file-coding-system} and uses that coding -system, by default, for operations that write from this buffer into a -file. This includes the commands @code{save-buffer} and -@code{write-region}. If you want to write files from this buffer using -a different coding system, you can specify a different coding system for -the buffer using @code{set-buffer-file-coding-system} (@pxref{Text -Coding}). - - You can insert any possible character into any Emacs buffer, but -most coding systems can only handle some of the possible characters. -This means that it is possible for you to 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 the buffer, Emacs cannot use the current value of +coding system in @code{buffer-file-coding-system}. That makes it the +default for operations that write from this buffer into a file, such +as @code{save-buffer} and @code{write-region}. You can specify a +different coding system for further file output from the buffer using +@code{set-buffer-file-coding-system} (@pxref{Text Coding}). + + 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 +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. @@ -896,12 +925,12 @@ 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 most-preferred coding system is recommended for use in MIME messages; -if not, Emacs tells you that the most-preferred coding system is -not recommended and prompts you for another coding system. This is so -you won't inadvertently send a message encoded in a way that your -recipient's mail software will have difficulty decoding. (If you do -want to use the most-preferred coding system, you can still type its -name in response to the question.) +if not, Emacs tells you that the most-preferred coding system is not +recommended and prompts you for another coding system. This is so you +won't inadvertently send a message encoded in a way that your +recipient's mail software will have difficulty decoding. (You can +still use an unsuitable coding system if you type its name in response +to the question.) @vindex sendmail-coding-system When you send a message with Mail mode (@pxref{Sending Mail}), Emacs has @@ -914,21 +943,6 @@ new files, which is controlled by your choice of language environment, if that is non-@code{nil}. If all of these three values are @code{nil}, Emacs encodes outgoing mail using the Latin-1 coding system. -@vindex rmail-decode-mime-charset - 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). - @node Text Coding @section Specifying a Coding System for File Text -- 2.39.2