[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Emacs-diffs] Changes to nonascii.texi
|
From: |
Glenn Morris |
|
Subject: |
[Emacs-diffs] Changes to nonascii.texi |
|
Date: |
Thu, 06 Sep 2007 04:13:25 +0000 |
CVSROOT: /sources/emacs
Module name: emacs
Changes by: Glenn Morris <gm> 07/09/06 04:13:24
Index: nonascii.texi
===================================================================
RCS file: nonascii.texi
diff -N nonascii.texi
--- nonascii.texi 26 Jun 2007 00:29:23 -0000 1.70
+++ /dev/null 1 Jan 1970 00:00:00 -0000
@@ -1,1504 +0,0 @@
address@hidden -*-texinfo-*-
address@hidden This is part of the GNU Emacs Lisp Reference Manual.
address@hidden Copyright (C) 1998, 1999, 2001, 2002, 2003, 2004,
address@hidden 2005, 2006, 2007 Free Software Foundation, Inc.
address@hidden See the file elisp.texi for copying conditions.
address@hidden ../info/characters
address@hidden Non-ASCII Characters, Searching and Matching, Text, Top
address@hidden address@hidden Characters
address@hidden multibyte characters
address@hidden characters, multi-byte
address@hidden address@hidden characters
-
- This chapter covers the special issues relating to address@hidden
-characters and how they are stored in strings and buffers.
-
address@hidden
-* Text Representations:: Unibyte and multibyte representations
-* Converting Representations:: Converting unibyte to multibyte and vice versa.
-* Selecting a Representation:: Treating a byte sequence as unibyte or multi.
-* Character Codes:: How unibyte and multibyte relate to
- codes of individual characters.
-* Character Sets:: The space of possible character codes
- is divided into various character sets.
-* Chars and Bytes:: More information about multibyte encodings.
-* Splitting Characters:: Converting a character to its byte sequence.
-* Scanning Charsets:: Which character sets are used in a buffer?
-* Translation of Characters:: Translation tables are used for conversion.
-* Coding Systems:: Coding systems are conversions for saving files.
-* Input Methods:: Input methods allow users to enter various
- non-ASCII characters without special keyboards.
-* Locales:: Interacting with the POSIX locale.
address@hidden menu
-
address@hidden Text Representations
address@hidden Text Representations
address@hidden text representations
-
- Emacs has two @dfn{text representations}---two ways to represent text
-in a string or buffer. These are called @dfn{unibyte} and
address@hidden Each string, and each buffer, uses one of these two
-representations. For most purposes, you can ignore the issue of
-representations, because Emacs converts text between them as
-appropriate. Occasionally in Lisp programming you will need to pay
-attention to the difference.
-
address@hidden unibyte text
- In unibyte representation, each character occupies one byte and
-therefore the possible character codes range from 0 to 255. Codes 0
-through 127 are @acronym{ASCII} characters; the codes from 128 through 255
-are used for one address@hidden character set (you can choose which
-character set by setting the variable @code{nonascii-insert-offset}).
-
address@hidden leading code
address@hidden multibyte text
address@hidden trailing codes
- In multibyte representation, a character may occupy more than one
-byte, and as a result, the full range of Emacs character codes can be
-stored. The first byte of a multibyte character is always in the range
-128 through 159 (octal 0200 through 0237). These values are called
address@hidden codes}. The second and subsequent bytes of a multibyte
-character are always in the range 160 through 255 (octal 0240 through
-0377); these values are @dfn{trailing codes}.
-
- Some sequences of bytes are not valid in multibyte text: for example,
-a single isolated byte in the range 128 through 159 is not allowed. But
-character codes 128 through 159 can appear in multibyte text,
-represented as two-byte sequences. All the character codes 128 through
-255 are possible (though slightly abnormal) in multibyte text; they
-appear in multibyte buffers and strings when you do explicit encoding
-and decoding (@pxref{Explicit Encoding}).
-
- In a buffer, the buffer-local value of the variable
address@hidden specifies the representation used.
-The representation for a string is determined and recorded in the string
-when the string is constructed.
-
address@hidden enable-multibyte-characters
-This variable specifies the current buffer's text representation.
-If it is address@hidden, the buffer contains multibyte text; otherwise,
-it contains unibyte text.
-
-You cannot set this variable directly; instead, use the function
address@hidden to change a buffer's representation.
address@hidden defvar
-
address@hidden default-enable-multibyte-characters
-This variable's value is entirely equivalent to @code{(default-value
-'enable-multibyte-characters)}, and setting this variable changes that
-default value. Setting the local binding of
address@hidden in a specific buffer is not allowed,
-but changing the default value is supported, and it is a reasonable
-thing to do, because it has no effect on existing buffers.
-
-The @samp{--unibyte} command line option does its job by setting the
-default value to @code{nil} early in startup.
address@hidden defvar
-
address@hidden position-bytes position
-Return the byte-position corresponding to buffer position
address@hidden in the current buffer. This is 1 at the start of the
-buffer, and counts upward in bytes. If @var{position} is out of
-range, the value is @code{nil}.
address@hidden defun
-
address@hidden byte-to-position byte-position
-Return the buffer position corresponding to byte-position
address@hidden in the current buffer. If @var{byte-position} is
-out of range, the value is @code{nil}.
address@hidden defun
-
address@hidden multibyte-string-p string
-Return @code{t} if @var{string} is a multibyte string.
address@hidden defun
-
address@hidden string-bytes string
address@hidden string, number of bytes
-This function returns the number of bytes in @var{string}.
-If @var{string} is a multibyte string, this can be greater than
address@hidden(length @var{string})}.
address@hidden defun
-
address@hidden Converting Representations
address@hidden Converting Text Representations
-
- Emacs can convert unibyte text to multibyte; it can also convert
-multibyte text to unibyte, though this conversion loses information. In
-general these conversions happen when inserting text into a buffer, or
-when putting text from several strings together in one string. You can
-also explicitly convert a string's contents to either representation.
-
- Emacs chooses the representation for a string based on the text that
-it is constructed from. The general rule is to convert unibyte text to
-multibyte text when combining it with other multibyte text, because the
-multibyte representation is more general and can hold whatever
-characters the unibyte text has.
-
- When inserting text into a buffer, Emacs converts the text to the
-buffer's representation, as specified by
address@hidden in that buffer. In particular, when
-you insert multibyte text into a unibyte buffer, Emacs converts the text
-to unibyte, even though this conversion cannot in general preserve all
-the characters that might be in the multibyte text. The other natural
-alternative, to convert the buffer contents to multibyte, is not
-acceptable because the buffer's representation is a choice made by the
-user that cannot be overridden automatically.
-
- Converting unibyte text to multibyte text leaves @acronym{ASCII} characters
-unchanged, and likewise character codes 128 through 159. It converts
-the address@hidden codes 160 through 255 by adding the value
address@hidden to each character code. By setting this
-variable, you specify which character set the unibyte characters
-correspond to (@pxref{Character Sets}). For example, if
address@hidden is 2048, which is @code{(- (make-char
-'latin-iso8859-1) 128)}, then the unibyte address@hidden characters
-correspond to Latin 1. If it is 2688, which is @code{(- (make-char
-'greek-iso8859-7) 128)}, then they correspond to Greek letters.
-
- Converting multibyte text to unibyte is simpler: it discards all but
-the low 8 bits of each character code. If @code{nonascii-insert-offset}
-has a reasonable value, corresponding to the beginning of some character
-set, this conversion is the inverse of the other: converting unibyte
-text to multibyte and back to unibyte reproduces the original unibyte
-text.
-
address@hidden nonascii-insert-offset
-This variable specifies the amount to add to a address@hidden character
-when converting unibyte text to multibyte. It also applies when
address@hidden inserts a character in the unibyte
address@hidden range, 128 through 255. However, the functions
address@hidden and @code{insert-char} do not perform this conversion.
-
-The right value to use to select character set @var{cs} is @code{(-
-(make-char @var{cs}) 128)}. If the value of
address@hidden is zero, then conversion actually uses the
-value for the Latin 1 character set, rather than zero.
address@hidden defvar
-
address@hidden nonascii-translation-table
-This variable provides a more general alternative to
address@hidden You can use it to specify independently
-how to translate each code in the range of 128 through 255 into a
-multibyte character. The value should be a char-table, or @code{nil}.
-If this is address@hidden, it overrides @code{nonascii-insert-offset}.
address@hidden defvar
-
-The next three functions either return the argument @var{string}, or a
-newly created string with no text properties.
-
address@hidden string-make-unibyte string
-This function converts the text of @var{string} to unibyte
-representation, if it isn't already, and returns the result. If
address@hidden is a unibyte string, it is returned unchanged. Multibyte
-character codes are converted to unibyte according to
address@hidden or, if that is @code{nil}, using
address@hidden If the lookup in the translation table
-fails, this function takes just the low 8 bits of each character.
address@hidden defun
-
address@hidden string-make-multibyte string
-This function converts the text of @var{string} to multibyte
-representation, if it isn't already, and returns the result. If
address@hidden is a multibyte string or consists entirely of
address@hidden characters, it is returned unchanged. In particular,
-if @var{string} is unibyte and entirely @acronym{ASCII}, the returned
-string is unibyte. (When the characters are all @acronym{ASCII},
-Emacs primitives will treat the string the same way whether it is
-unibyte or multibyte.) If @var{string} is unibyte and contains
address@hidden characters, the function
address@hidden is used to convert each unibyte
-character to a multibyte character.
address@hidden defun
-
address@hidden string-to-multibyte string
-This function returns a multibyte string containing the same sequence
-of character codes as @var{string}. Unlike
address@hidden, this function unconditionally returns a
-multibyte string. If @var{string} is a multibyte string, it is
-returned unchanged.
address@hidden defun
-
address@hidden multibyte-char-to-unibyte char
-This convert the multibyte character @var{char} to a unibyte
-character, based on @code{nonascii-translation-table} and
address@hidden
address@hidden defun
-
address@hidden unibyte-char-to-multibyte char
-This convert the unibyte character @var{char} to a multibyte
-character, based on @code{nonascii-translation-table} and
address@hidden
address@hidden defun
-
address@hidden Selecting a Representation
address@hidden Selecting a Representation
-
- Sometimes it is useful to examine an existing buffer or string as
-multibyte when it was unibyte, or vice versa.
-
address@hidden set-buffer-multibyte multibyte
-Set the representation type of the current buffer. If @var{multibyte}
-is address@hidden, the buffer becomes multibyte. If @var{multibyte}
-is @code{nil}, the buffer becomes unibyte.
-
-This function leaves the buffer contents unchanged when viewed as a
-sequence of bytes. As a consequence, it can change the contents viewed
-as characters; a sequence of two bytes which is treated as one character
-in multibyte representation will count as two characters in unibyte
-representation. Character codes 128 through 159 are an exception. They
-are represented by one byte in a unibyte buffer, but when the buffer is
-set to multibyte, they are converted to two-byte sequences, and vice
-versa.
-
-This function sets @code{enable-multibyte-characters} to record which
-representation is in use. It also adjusts various data in the buffer
-(including overlays, text properties and markers) so that they cover the
-same text as they did before.
-
-You cannot use @code{set-buffer-multibyte} on an indirect buffer,
-because indirect buffers always inherit the representation of the
-base buffer.
address@hidden defun
-
address@hidden string-as-unibyte string
-This function returns a string with the same bytes as @var{string} but
-treating each byte as a character. This means that the value may have
-more characters than @var{string} has.
-
-If @var{string} is already a unibyte string, then the value is
address@hidden itself. Otherwise it is a newly created string, with no
-text properties. If @var{string} is multibyte, any characters it
-contains of charset @code{eight-bit-control} or @code{eight-bit-graphic}
-are converted to the corresponding single byte.
address@hidden defun
-
address@hidden string-as-multibyte string
-This function returns a string with the same bytes as @var{string} but
-treating each multibyte sequence as one character. This means that the
-value may have fewer characters than @var{string} has.
-
-If @var{string} is already a multibyte string, then the value is
address@hidden itself. Otherwise it is a newly created string, with no
-text properties. If @var{string} is unibyte and contains any individual
-8-bit bytes (i.e.@: not part of a multibyte form), they are converted to
-the corresponding multibyte character of charset @code{eight-bit-control}
-or @code{eight-bit-graphic}.
address@hidden defun
-
address@hidden Character Codes
address@hidden Character Codes
address@hidden character codes
-
- The unibyte and multibyte text representations use different character
-codes. The valid character codes for unibyte representation range from
-0 to 255---the values that can fit in one byte. The valid character
-codes for multibyte representation range from 0 to 524287, but not all
-values in that range are valid. The values 128 through 255 are not
-entirely proper in multibyte text, but they can occur if you do explicit
-encoding and decoding (@pxref{Explicit Encoding}). Some other character
-codes cannot occur at all in multibyte text. Only the @acronym{ASCII} codes
-0 through 127 are completely legitimate in both representations.
-
address@hidden char-valid-p charcode &optional genericp
-This returns @code{t} if @var{charcode} is valid (either for unibyte
-text or for multibyte text).
-
address@hidden
-(char-valid-p 65)
- @result{} t
-(char-valid-p 256)
- @result{} nil
-(char-valid-p 2248)
- @result{} t
address@hidden example
-
-If the optional argument @var{genericp} is address@hidden, this
-function also returns @code{t} if @var{charcode} is a generic
-character (@pxref{Splitting Characters}).
address@hidden defun
-
address@hidden Character Sets
address@hidden Character Sets
address@hidden character sets
-
- Emacs classifies characters into various @dfn{character sets}, each of
-which has a name which is a symbol. Each character belongs to one and
-only one character set.
-
- In general, there is one character set for each distinct script. For
-example, @code{latin-iso8859-1} is one character set,
address@hidden is another, and @code{ascii} is another. An
-Emacs character set can hold at most 9025 characters; therefore, in some
-cases, characters that would logically be grouped together are split
-into several character sets. For example, one set of Chinese
-characters, generally known as Big 5, is divided into two Emacs
-character sets, @code{chinese-big5-1} and @code{chinese-big5-2}.
-
- @acronym{ASCII} characters are in character set @code{ascii}. The
address@hidden characters 128 through 159 are in character set
address@hidden, and codes 160 through 255 are in character set
address@hidden
-
address@hidden charsetp object
-Returns @code{t} if @var{object} is a symbol that names a character set,
address@hidden otherwise.
address@hidden defun
-
address@hidden charset-list
-The value is a list of all defined character set names.
address@hidden defvar
-
address@hidden charset-list
-This function returns the value of @code{charset-list}. It is only
-provided for backward compatibility.
address@hidden defun
-
address@hidden char-charset character
-This function returns the name of the character set that @var{character}
-belongs to, or the symbol @code{unknown} if @var{character} is not a
-valid character.
address@hidden defun
-
address@hidden charset-plist charset
-This function returns the charset property list of the character set
address@hidden Although @var{charset} is a symbol, this is not the same
-as the property list of that symbol. Charset properties are used for
-special purposes within Emacs.
address@hidden defun
-
address@hidden Command list-charset-chars charset
-This command displays a list of characters in the character set
address@hidden
address@hidden deffn
-
address@hidden Chars and Bytes
address@hidden Characters and Bytes
address@hidden bytes and characters
-
address@hidden introduction sequence (of character)
address@hidden dimension (of character set)
- In multibyte representation, each character occupies one or more
-bytes. Each character set has an @dfn{introduction sequence}, which is
-normally one or two bytes long. (Exception: the @code{ascii} character
-set and the @code{eight-bit-graphic} character set have a zero-length
-introduction sequence.) The introduction sequence is the beginning of
-the byte sequence for any character in the character set. The rest of
-the character's bytes distinguish it from the other characters in the
-same character set. Depending on the character set, there are either
-one or two distinguishing bytes; the number of such bytes is called the
address@hidden of the character set.
-
address@hidden charset-dimension charset
-This function returns the dimension of @var{charset}; at present, the
-dimension is always 1 or 2.
address@hidden defun
-
address@hidden charset-bytes charset
-This function returns the number of bytes used to represent a character
-in character set @var{charset}.
address@hidden defun
-
- This is the simplest way to determine the byte length of a character
-set's introduction sequence:
-
address@hidden
-(- (charset-bytes @var{charset})
- (charset-dimension @var{charset}))
address@hidden example
-
address@hidden Splitting Characters
address@hidden Splitting Characters
address@hidden character as bytes
-
- The functions in this section convert between characters and the byte
-values used to represent them. For most purposes, there is no need to
-be concerned with the sequence of bytes used to represent a character,
-because Emacs translates automatically when necessary.
-
address@hidden split-char character
-Return a list containing the name of the character set of
address@hidden, followed by one or two byte values (integers) which
-identify @var{character} within that character set. The number of byte
-values is the character set's dimension.
-
-If @var{character} is invalid as a character code, @code{split-char}
-returns a list consisting of the symbol @code{unknown} and @var{character}.
-
address@hidden
-(split-char 2248)
- @result{} (latin-iso8859-1 72)
-(split-char 65)
- @result{} (ascii 65)
-(split-char 128)
- @result{} (eight-bit-control 128)
address@hidden example
address@hidden defun
-
address@hidden generate characters in charsets
address@hidden make-char charset &optional code1 code2
-This function returns the character in character set @var{charset} whose
-position codes are @var{code1} and @var{code2}. This is roughly the
-inverse of @code{split-char}. Normally, you should specify either one
-or both of @var{code1} and @var{code2} according to the dimension of
address@hidden For example,
-
address@hidden
-(make-char 'latin-iso8859-1 72)
- @result{} 2248
address@hidden example
-
-Actually, the eighth bit of both @var{code1} and @var{code2} is zeroed
-before they are used to index @var{charset}. Thus you may use, for
-instance, an ISO 8859 character code rather than subtracting 128, as
-is necessary to index the corresponding Emacs charset.
address@hidden defun
-
address@hidden generic characters
- If you call @code{make-char} with no @var{byte-values}, the result is
-a @dfn{generic character} which stands for @var{charset}. A generic
-character is an integer, but it is @emph{not} valid for insertion in the
-buffer as a character. It can be used in @code{char-table-range} to
-refer to the whole character set (@pxref{Char-Tables}).
address@hidden returns @code{nil} for generic characters.
-For example:
-
address@hidden
-(make-char 'latin-iso8859-1)
- @result{} 2176
-(char-valid-p 2176)
- @result{} nil
-(char-valid-p 2176 t)
- @result{} t
-(split-char 2176)
- @result{} (latin-iso8859-1 0)
address@hidden example
-
-The character sets @code{ascii}, @code{eight-bit-control}, and
address@hidden don't have corresponding generic characters. If
address@hidden is one of them and you don't supply @var{code1},
address@hidden returns the character code corresponding to the
-smallest code in @var{charset}.
-
address@hidden Scanning Charsets
address@hidden Scanning for Character Sets
-
- Sometimes it is useful to find out which character sets appear in a
-part of a buffer or a string. One use for this is in determining which
-coding systems (@pxref{Coding Systems}) are capable of representing all
-of the text in question.
-
address@hidden charset-after &optional pos
-This function return the charset of a character in the current buffer
-at position @var{pos}. If @var{pos} is omitted or @code{nil}, it
-defaults to the current value of point. If @var{pos} is out of range,
-the value is @code{nil}.
address@hidden defun
-
address@hidden find-charset-region beg end &optional translation
-This function returns a list of the character sets that appear in the
-current buffer between positions @var{beg} and @var{end}.
-
-The optional argument @var{translation} specifies a translation table to
-be used in scanning the text (@pxref{Translation of Characters}). If it
-is address@hidden, then each character in the region is translated
-through this table, and the value returned describes the translated
-characters instead of the characters actually in the buffer.
address@hidden defun
-
address@hidden find-charset-string string &optional translation
-This function returns a list of the character sets that appear in the
-string @var{string}. It is just like @code{find-charset-region}, except
-that it applies to the contents of @var{string} instead of part of the
-current buffer.
address@hidden defun
-
address@hidden Translation of Characters
address@hidden Translation of Characters
address@hidden character translation tables
address@hidden translation tables
-
- A @dfn{translation table} is a char-table that specifies a mapping
-of characters into characters. These tables are used in encoding and
-decoding, and for other purposes. Some coding systems specify their
-own particular translation tables; there are also default translation
-tables which apply to all other coding systems.
-
- For instance, the coding-system @code{utf-8} has a translation table
-that maps characters of various charsets (e.g.,
address@hidden@var{x}}) into Unicode character sets. This way,
-it can encode Latin-2 characters into UTF-8. Meanwhile,
address@hidden operates by specifying
address@hidden to translate
address@hidden characters into corresponding Unicode characters.
-
address@hidden make-translation-table &rest translations
-This function returns a translation table based on the argument
address@hidden Each element of @var{translations} should be a
-list of elements of the form @code{(@var{from} . @var{to})}; this says
-to translate the character @var{from} into @var{to}.
-
-The arguments and the forms in each argument are processed in order,
-and if a previous form already translates @var{to} to some other
-character, say @var{to-alt}, @var{from} is also translated to
address@hidden
-
-You can also map one whole character set into another character set with
-the same dimension. To do this, you specify a generic character (which
-designates a character set) for @var{from} (@pxref{Splitting Characters}).
-In this case, if @var{to} is also a generic character, its character
-set should have the same dimension as @var{from}'s. Then the
-translation table translates each character of @var{from}'s character
-set into the corresponding character of @var{to}'s character set. If
address@hidden is a generic character and @var{to} is an ordinary
-character, then the translation table translates every character of
address@hidden's character set into @var{to}.
address@hidden defun
-
- In decoding, the translation table's translations are applied to the
-characters that result from ordinary decoding. If a coding system has
-property @code{translation-table-for-decode}, that specifies the
-translation table to use. (This is a property of the coding system,
-as returned by @code{coding-system-get}, not a property of the symbol
-that is the coding system's name. @xref{Coding System Basics,, Basic
-Concepts of Coding Systems}.) Otherwise, if
address@hidden is address@hidden,
-decoding uses that table.
-
- In encoding, the translation table's translations are applied to the
-characters in the buffer, and the result of translation is actually
-encoded. If a coding system has property
address@hidden, that specifies the translation
-table to use. Otherwise the variable
address@hidden specifies the translation
-table.
-
address@hidden standard-translation-table-for-decode
-This is the default translation table for decoding, for
-coding systems that don't specify any other translation table.
address@hidden defvar
-
address@hidden standard-translation-table-for-encode
-This is the default translation table for encoding, for
-coding systems that don't specify any other translation table.
address@hidden defvar
-
address@hidden translation-table-for-input
-Self-inserting characters are translated through this translation
-table before they are inserted. Search commands also translate their
-input through this table, so they can compare more reliably with
-what's in the buffer.
-
address@hidden sets this variable so that your
-keyboard input gets translated into the character sets that the buffer
-is likely to contain. This variable automatically becomes
-buffer-local when set.
address@hidden defvar
-
address@hidden Coding Systems
address@hidden Coding Systems
-
address@hidden coding system
- When Emacs reads or writes a file, and when Emacs sends text to a
-subprocess or receives text from a subprocess, it normally performs
-character code conversion and end-of-line conversion as specified
-by a particular @dfn{coding system}.
-
- How to define a coding system is an arcane matter, and is not
-documented here.
-
address@hidden
-* Coding System Basics:: Basic concepts.
-* Encoding and I/O:: How file I/O functions handle coding systems.
-* Lisp and Coding Systems:: Functions to operate on coding system names.
-* User-Chosen Coding Systems:: Asking the user to choose a coding system.
-* Default Coding Systems:: Controlling the default choices.
-* Specifying Coding Systems:: Requesting a particular coding system
- for a single file operation.
-* Explicit Encoding:: Encoding or decoding text without doing I/O.
-* Terminal I/O Encoding:: Use of encoding for terminal I/O.
-* MS-DOS File Types:: How DOS "text" and "binary" files
- relate to coding systems.
address@hidden menu
-
address@hidden Coding System Basics
address@hidden Basic Concepts of Coding Systems
-
address@hidden character code conversion
- @dfn{Character code conversion} involves conversion between the encoding
-used inside Emacs and some other encoding. Emacs supports many
-different encodings, in that it can convert to and from them. For
-example, it can convert text to or from encodings such as Latin 1, Latin
-2, Latin 3, Latin 4, Latin 5, and several variants of ISO 2022. In some
-cases, Emacs supports several alternative encodings for the same
-characters; for example, there are three coding systems for the Cyrillic
-(Russian) alphabet: ISO, Alternativnyj, and KOI8.
-
- Most coding systems specify a particular character code for
-conversion, but some of them leave the choice unspecified---to be chosen
-heuristically for each file, based on the data.
-
- In general, a coding system doesn't guarantee roundtrip identity:
-decoding a byte sequence using coding system, then encoding the
-resulting text in the same coding system, can produce a different byte
-sequence. However, the following coding systems do guarantee that the
-byte sequence will be the same as what you originally decoded:
-
address@hidden
-chinese-big5 chinese-iso-8bit cyrillic-iso-8bit emacs-mule
-greek-iso-8bit hebrew-iso-8bit iso-latin-1 iso-latin-2 iso-latin-3
-iso-latin-4 iso-latin-5 iso-latin-8 iso-latin-9 iso-safe
-japanese-iso-8bit japanese-shift-jis korean-iso-8bit raw-text
address@hidden quotation
-
- Encoding buffer text and then decoding the result can also fail to
-reproduce the original text. For instance, if you encode Latin-2
-characters with @code{utf-8} and decode the result using the same
-coding system, you'll get Unicode characters (of charset
address@hidden). If you encode Unicode characters with
address@hidden and decode the result with the same coding system,
-you'll get Latin-2 characters.
-
address@hidden EOL conversion
address@hidden end-of-line conversion
address@hidden line end conversion
- @dfn{End of line conversion} handles three different conventions used
-on various systems for representing end of line in files. The Unix
-convention is to use the linefeed character (also called newline). The
-DOS convention is to use a carriage-return and a linefeed at the end of
-a line. The Mac convention is to use just carriage-return.
-
address@hidden base coding system
address@hidden variant coding system
- @dfn{Base coding systems} such as @code{latin-1} leave the end-of-line
-conversion unspecified, to be chosen based on the data. @dfn{Variant
-coding systems} such as @code{latin-1-unix}, @code{latin-1-dos} and
address@hidden specify the end-of-line conversion explicitly as
-well. Most base coding systems have three corresponding variants whose
-names are formed by adding @samp{-unix}, @samp{-dos} and @samp{-mac}.
-
- The coding system @code{raw-text} is special in that it prevents
-character code conversion, and causes the buffer visited with that
-coding system to be a unibyte buffer. It does not specify the
-end-of-line conversion, allowing that to be determined as usual by the
-data, and has the usual three variants which specify the end-of-line
-conversion. @code{no-conversion} is equivalent to @code{raw-text-unix}:
-it specifies no conversion of either character codes or end-of-line.
-
- The coding system @code{emacs-mule} specifies that the data is
-represented in the internal Emacs encoding. This is like
address@hidden in that no code conversion happens, but different in
-that the result is multibyte data.
-
address@hidden coding-system-get coding-system property
-This function returns the specified property of the coding system
address@hidden Most coding system properties exist for internal
-purposes, but one that you might find useful is @code{mime-charset}.
-That property's value is the name used in MIME for the character coding
-which this coding system can read and write. Examples:
-
address@hidden
-(coding-system-get 'iso-latin-1 'mime-charset)
- @result{} iso-8859-1
-(coding-system-get 'iso-2022-cn 'mime-charset)
- @result{} iso-2022-cn
-(coding-system-get 'cyrillic-koi8 'mime-charset)
- @result{} koi8-r
address@hidden example
-
-The value of the @code{mime-charset} property is also defined
-as an alias for the coding system.
address@hidden defun
-
address@hidden Encoding and I/O
address@hidden Encoding and I/O
-
- The principal purpose of coding systems is for use in reading and
-writing files. The function @code{insert-file-contents} uses
-a coding system for decoding the file data, and @code{write-region}
-uses one to encode the buffer contents.
-
- You can specify the coding system to use either explicitly
-(@pxref{Specifying Coding Systems}), or implicitly using a default
-mechanism (@pxref{Default Coding Systems}). But these methods may not
-completely specify what to do. For example, they may choose a coding
-system such as @code{undefined} which leaves the character code
-conversion to be determined from the data. In these cases, the I/O
-operation finishes the job of choosing a coding system. Very often
-you will want to find out afterwards which coding system was chosen.
-
address@hidden buffer-file-coding-system
-This buffer-local variable records the coding system that was used to visit
-the current buffer. It is used for saving the buffer, and for writing part
-of the buffer with @code{write-region}. If the text to be written
-cannot be safely encoded using the coding system specified by this
-variable, these operations select an alternative encoding by calling
-the function @code{select-safe-coding-system} (@pxref{User-Chosen
-Coding Systems}). If selecting a different encoding requires to ask
-the user to specify a coding system, @code{buffer-file-coding-system}
-is updated to the newly selected coding system.
-
address@hidden does @emph{not} affect sending text
-to a subprocess.
address@hidden defvar
-
address@hidden save-buffer-coding-system
-This variable specifies the coding system for saving the buffer (by
-overriding @code{buffer-file-coding-system}). Note that it is not used
-for @code{write-region}.
-
-When a command to save the buffer starts out to use
address@hidden (or @code{save-buffer-coding-system}),
-and that coding system cannot handle
-the actual text in the buffer, the command asks the user to choose
-another coding system (by calling @code{select-safe-coding-system}).
-After that happens, the command also updates
address@hidden to represent the coding system that
-the user specified.
address@hidden defvar
-
address@hidden last-coding-system-used
-I/O operations for files and subprocesses set this variable to the
-coding system name that was used. The explicit encoding and decoding
-functions (@pxref{Explicit Encoding}) set it too.
-
address@hidden:} Since receiving subprocess output sets this variable,
-it can change whenever Emacs waits; therefore, you should copy the
-value shortly after the function call that stores the value you are
-interested in.
address@hidden defvar
-
- The variable @code{selection-coding-system} specifies how to encode
-selections for the window system. @xref{Window System Selections}.
-
address@hidden file-name-coding-system
-The variable @code{file-name-coding-system} specifies the coding
-system to use for encoding file names. Emacs encodes file names using
-that coding system for all file operations. If
address@hidden is @code{nil}, Emacs uses a default
-coding system determined by the selected language environment. In the
-default language environment, any address@hidden characters in
-file names are not encoded specially; they appear in the file system
-using the internal Emacs representation.
address@hidden defvar
-
- @strong{Warning:} if you change @code{file-name-coding-system} (or
-the language environment) in the middle of an Emacs session, problems
-can result if you have already visited files whose names were encoded
-using the earlier coding system and are handled differently under the
-new coding system. If you try to save one of these buffers under the
-visited file name, saving may use the wrong file name, or it may get
-an error. If such a problem happens, use @kbd{C-x C-w} to specify a
-new file name for that buffer.
-
address@hidden Lisp and Coding Systems
address@hidden Coding Systems in Lisp
-
- Here are the Lisp facilities for working with coding systems:
-
address@hidden coding-system-list &optional base-only
-This function returns a list of all coding system names (symbols). If
address@hidden is address@hidden, the value includes only the
-base coding systems. Otherwise, it includes alias and variant coding
-systems as well.
address@hidden defun
-
address@hidden coding-system-p object
-This function returns @code{t} if @var{object} is a coding system
-name or @code{nil}.
address@hidden defun
-
address@hidden check-coding-system coding-system
-This function checks the validity of @var{coding-system}.
-If that is valid, it returns @var{coding-system}.
-Otherwise it signals an error with condition @code{coding-system-error}.
address@hidden defun
-
address@hidden coding-system-eol-type coding-system
-This function returns the type of end-of-line (a.k.a.@: @dfn{eol})
-conversion used by @var{coding-system}. If @var{coding-system}
-specifies a certain eol conversion, the return value is an integer 0,
-1, or 2, standing for @code{unix}, @code{dos}, and @code{mac},
-respectively. If @var{coding-system} doesn't specify eol conversion
-explicitly, the return value is a vector of coding systems, each one
-with one of the possible eol conversion types, like this:
-
address@hidden
-(coding-system-eol-type 'latin-1)
- @result{} [latin-1-unix latin-1-dos latin-1-mac]
address@hidden lisp
-
address@hidden
-If this function returns a vector, Emacs will decide, as part of the
-text encoding or decoding process, what eol conversion to use. For
-decoding, the end-of-line format of the text is auto-detected, and the
-eol conversion is set to match it (e.g., DOS-style CRLF format will
-imply @code{dos} eol conversion). For encoding, the eol conversion is
-taken from the appropriate default coding system (e.g.,
address@hidden for
address@hidden), or from the default eol conversion
-appropriate for the underlying platform.
address@hidden defun
-
address@hidden coding-system-change-eol-conversion coding-system eol-type
-This function returns a coding system which is like @var{coding-system}
-except for its eol conversion, which is specified by @code{eol-type}.
address@hidden should be @code{unix}, @code{dos}, @code{mac}, or
address@hidden If it is @code{nil}, the returned coding system determines
-the end-of-line conversion from the data.
-
address@hidden may also be 0, 1 or 2, standing for @code{unix},
address@hidden and @code{mac}, respectively.
address@hidden defun
-
address@hidden coding-system-change-text-conversion eol-coding text-coding
-This function returns a coding system which uses the end-of-line
-conversion of @var{eol-coding}, and the text conversion of
address@hidden If @var{text-coding} is @code{nil}, it returns
address@hidden, or one of its variants according to @var{eol-coding}.
address@hidden defun
-
address@hidden find-coding-systems-region from to
-This function returns a list of coding systems that could be used to
-encode a text between @var{from} and @var{to}. All coding systems in
-the list can safely encode any multibyte characters in that portion of
-the text.
-
-If the text contains no multibyte characters, the function returns the
-list @code{(undecided)}.
address@hidden defun
-
address@hidden find-coding-systems-string string
-This function returns a list of coding systems that could be used to
-encode the text of @var{string}. All coding systems in the list can
-safely encode any multibyte characters in @var{string}. If the text
-contains no multibyte characters, this returns the list
address@hidden(undecided)}.
address@hidden defun
-
address@hidden find-coding-systems-for-charsets charsets
-This function returns a list of coding systems that could be used to
-encode all the character sets in the list @var{charsets}.
address@hidden defun
-
address@hidden detect-coding-region start end &optional highest
-This function chooses a plausible coding system for decoding the text
-from @var{start} to @var{end}. This text should be a byte sequence
-(@pxref{Explicit Encoding}).
-
-Normally this function returns a list of coding systems that could
-handle decoding the text that was scanned. They are listed in order of
-decreasing priority. But if @var{highest} is address@hidden, then the
-return value is just one coding system, the one that is highest in
-priority.
-
-If the region contains only @acronym{ASCII} characters except for such
-ISO-2022 control characters ISO-2022 as @code{ESC}, the value is
address@hidden or @code{(undecided)}, or a variant specifying
-end-of-line conversion, if that can be deduced from the text.
address@hidden defun
-
address@hidden detect-coding-string string &optional highest
-This function is like @code{detect-coding-region} except that it
-operates on the contents of @var{string} instead of bytes in the buffer.
address@hidden defun
-
- @xref{Coding systems for a subprocess,, Process Information}, in
-particular the description of the functions
address@hidden and @code{set-process-coding-system}, for
-how to examine or set the coding systems used for I/O to a subprocess.
-
address@hidden User-Chosen Coding Systems
address@hidden User-Chosen Coding Systems
-
address@hidden select safe coding system
address@hidden select-safe-coding-system from to &optional
default-coding-system accept-default-p file
-This function selects a coding system for encoding specified text,
-asking the user to choose if necessary. Normally the specified text
-is the text in the current buffer between @var{from} and @var{to}. If
address@hidden is a string, the string specifies the text to encode, and
address@hidden is ignored.
-
-If @var{default-coding-system} is address@hidden, that is the first
-coding system to try; if that can handle the text,
address@hidden returns that coding system. It can
-also be a list of coding systems; then the function tries each of them
-one by one. After trying all of them, it next tries the current
-buffer's value of @code{buffer-file-coding-system} (if it is not
address@hidden), then the value of
address@hidden and finally the user's most
-preferred coding system, which the user can set using the command
address@hidden (@pxref{Recognize Coding,, Recognizing
-Coding Systems, emacs, The GNU Emacs Manual}).
-
-If one of those coding systems can safely encode all the specified
-text, @code{select-safe-coding-system} chooses it and returns it.
-Otherwise, it asks the user to choose from a list of coding systems
-which can encode all the text, and returns the user's choice.
-
address@hidden can also be a list whose first element is
-t and whose other elements are coding systems. Then, if no coding
-system in the list can handle the text, @code{select-safe-coding-system}
-queries the user immediately, without trying any of the three
-alternatives described above.
-
-The optional argument @var{accept-default-p}, if address@hidden,
-should be a function to determine whether a coding system selected
-without user interaction is acceptable. @code{select-safe-coding-system}
-calls this function with one argument, the base coding system of the
-selected coding system. If @var{accept-default-p} returns @code{nil},
address@hidden rejects the silently selected coding
-system, and asks the user to select a coding system from a list of
-possible candidates.
-
address@hidden select-safe-coding-system-accept-default-p
-If the variable @code{select-safe-coding-system-accept-default-p} is
address@hidden, its value overrides the value of
address@hidden
-
-As a final step, before returning the chosen coding system,
address@hidden checks whether that coding system is
-consistent with what would be selected if the contents of the region
-were read from a file. (If not, this could lead to data corruption in
-a file subsequently re-visited and edited.) Normally,
address@hidden uses @code{buffer-file-name} as the
-file for this purpose, but if @var{file} is address@hidden, it uses
-that file instead (this can be relevant for @code{write-region} and
-similar functions). If it detects an apparent inconsistency,
address@hidden queries the user before selecting the
-coding system.
address@hidden defun
-
- Here are two functions you can use to let the user specify a coding
-system, with completion. @xref{Completion}.
-
address@hidden read-coding-system prompt &optional default
-This function reads a coding system using the minibuffer, prompting with
-string @var{prompt}, and returns the coding system name as a symbol. If
-the user enters null input, @var{default} specifies which coding system
-to return. It should be a symbol or a string.
address@hidden defun
-
address@hidden read-non-nil-coding-system prompt
-This function reads a coding system using the minibuffer, prompting with
-string @var{prompt}, and returns the coding system name as a symbol. If
-the user tries to enter null input, it asks the user to try again.
address@hidden Systems}.
address@hidden defun
-
address@hidden Default Coding Systems
address@hidden Default Coding Systems
-
- This section describes variables that specify the default coding
-system for certain files or when running certain subprograms, and the
-function that I/O operations use to access them.
-
- The idea of these variables is that you set them once and for all to the
-defaults you want, and then do not change them again. To specify a
-particular coding system for a particular operation in a Lisp program,
-don't change these variables; instead, override them using
address@hidden and @code{coding-system-for-write}
-(@pxref{Specifying Coding Systems}).
-
address@hidden auto-coding-regexp-alist
-This variable is an alist of text patterns and corresponding coding
-systems. Each element has the form @code{(@var{regexp}
-. @var{coding-system})}; a file whose first few kilobytes match
address@hidden is decoded with @var{coding-system} when its contents are
-read into a buffer. The settings in this alist take priority over
address@hidden:} tags in the files and the contents of
address@hidden (see below). The default value is set
-so that Emacs automatically recognizes mail files in Babyl format and
-reads them with no code conversions.
address@hidden defvar
-
address@hidden file-coding-system-alist
-This variable is an alist that specifies the coding systems to use for
-reading and writing particular files. Each element has the form
address@hidden(@var{pattern} . @var{coding})}, where @var{pattern} is a regular
-expression that matches certain file names. The element applies to file
-names that match @var{pattern}.
-
-The @sc{cdr} of the element, @var{coding}, should be either a coding
-system, a cons cell containing two coding systems, or a function name (a
-symbol with a function definition). If @var{coding} is a coding system,
-that coding system is used for both reading the file and writing it. If
address@hidden is a cons cell containing two coding systems, its @sc{car}
-specifies the coding system for decoding, and its @sc{cdr} specifies the
-coding system for encoding.
-
-If @var{coding} is a function name, the function should take one
-argument, a list of all arguments passed to
address@hidden It must return a coding system
-or a cons cell containing two coding systems. This value has the same
-meaning as described above.
-
-If @var{coding} (or what returned by the above function) is
address@hidden, the normal code-detection is performed.
address@hidden defvar
-
address@hidden process-coding-system-alist
-This variable is an alist specifying which coding systems to use for a
-subprocess, depending on which program is running in the subprocess. It
-works like @code{file-coding-system-alist}, except that @var{pattern} is
-matched against the program name used to start the subprocess. The coding
-system or systems specified in this alist are used to initialize the
-coding systems used for I/O to the subprocess, but you can specify
-other coding systems later using @code{set-process-coding-system}.
address@hidden defvar
-
- @strong{Warning:} Coding systems such as @code{undecided}, which
-determine the coding system from the data, do not work entirely reliably
-with asynchronous subprocess output. This is because Emacs handles
-asynchronous subprocess output in batches, as it arrives. If the coding
-system leaves the character code conversion unspecified, or leaves the
-end-of-line conversion unspecified, Emacs must try to detect the proper
-conversion from one batch at a time, and this does not always work.
-
- Therefore, with an asynchronous subprocess, if at all possible, use a
-coding system which determines both the character code conversion and
-the end of line conversion---that is, one like @code{latin-1-unix},
-rather than @code{undecided} or @code{latin-1}.
-
address@hidden network-coding-system-alist
-This variable is an alist that specifies the coding system to use for
-network streams. It works much like @code{file-coding-system-alist},
-with the difference that the @var{pattern} in an element may be either a
-port number or a regular expression. If it is a regular expression, it
-is matched against the network service name used to open the network
-stream.
address@hidden defvar
-
address@hidden default-process-coding-system
-This variable specifies the coding systems to use for subprocess (and
-network stream) input and output, when nothing else specifies what to
-do.
-
-The value should be a cons cell of the form @code{(@var{input-coding}
-. @var{output-coding})}. Here @var{input-coding} applies to input from
-the subprocess, and @var{output-coding} applies to output to it.
address@hidden defvar
-
address@hidden auto-coding-functions
-This variable holds a list of functions that try to determine a
-coding system for a file based on its undecoded contents.
-
-Each function in this list should be written to look at text in the
-current buffer, but should not modify it in any way. The buffer will
-contain undecoded text of parts of the file. Each function should
-take one argument, @var{size}, which tells it how many characters to
-look at, starting from point. If the function succeeds in determining
-a coding system for the file, it should return that coding system.
-Otherwise, it should return @code{nil}.
-
-If a file has a @samp{coding:} tag, that takes precedence, so these
-functions won't be called.
address@hidden defvar
-
address@hidden find-operation-coding-system operation &rest arguments
-This function returns the coding system to use (by default) for
-performing @var{operation} with @var{arguments}. The value has this
-form:
-
address@hidden
-(@var{decoding-system} . @var{encoding-system})
address@hidden example
-
-The first element, @var{decoding-system}, is the coding system to use
-for decoding (in case @var{operation} does decoding), and
address@hidden is the coding system for encoding (in case
address@hidden does encoding).
-
-The argument @var{operation} is a symbol, one of @code{write-region},
address@hidden, @code{call-process}, @code{call-process-region},
address@hidden, or @code{open-network-stream}. These are
-the names of the Emacs I/O primitives that can do character code and
-eol conversion.
-
-The remaining arguments should be the same arguments that might be given
-to the corresponding I/O primitive. Depending on the primitive, one
-of those arguments is selected as the @dfn{target}. For example, if
address@hidden does file I/O, whichever argument specifies the file
-name is the target. For subprocess primitives, the process name is the
-target. For @code{open-network-stream}, the target is the service name
-or port number.
-
-Depending on @var{operation}, this function looks up the target in
address@hidden, @code{process-coding-system-alist},
-or @code{network-coding-system-alist}. If the target is found in the
-alist, @code{find-operation-coding-system} returns its association in
-the alist; otherwise it returns @code{nil}.
-
-If @var{operation} is @code{insert-file-contents}, the argument
-corresponding to the target may be a cons cell of the form
address@hidden(@var{filename} . @var{buffer})}). In that case, @var{filename}
-is a file name to look up in @code{file-coding-system-alist}, and
address@hidden is a buffer that contains the file's contents (not yet
-decoded). If @code{file-coding-system-alist} specifies a function to
-call for this file, and that function needs to examine the file's
-contents (as it usually does), it should examine the contents of
address@hidden instead of reading the file.
address@hidden defun
-
address@hidden Specifying Coding Systems
address@hidden Specifying a Coding System for One Operation
-
- You can specify the coding system for a specific operation by binding
-the variables @code{coding-system-for-read} and/or
address@hidden
-
address@hidden coding-system-for-read
-If this variable is address@hidden, it specifies the coding system to
-use for reading a file, or for input from a synchronous subprocess.
-
-It also applies to any asynchronous subprocess or network stream, but in
-a different way: the value of @code{coding-system-for-read} when you
-start the subprocess or open the network stream specifies the input
-decoding method for that subprocess or network stream. It remains in
-use for that subprocess or network stream unless and until overridden.
-
-The right way to use this variable is to bind it with @code{let} for a
-specific I/O operation. Its global value is normally @code{nil}, and
-you should not globally set it to any other value. Here is an example
-of the right way to use the variable:
-
address@hidden
-;; @r{Read the file with no character code conversion.}
-;; @r{Assume @acronym{crlf} represents end-of-line.}
-(let ((coding-system-for-read 'emacs-mule-dos))
- (insert-file-contents filename))
address@hidden example
-
-When its value is address@hidden, this variable takes precedence over
-all other methods of specifying a coding system to use for input,
-including @code{file-coding-system-alist},
address@hidden and
address@hidden
address@hidden defvar
-
address@hidden coding-system-for-write
-This works much like @code{coding-system-for-read}, except that it
-applies to output rather than input. It affects writing to files,
-as well as sending output to subprocesses and net connections.
-
-When a single operation does both input and output, as do
address@hidden and @code{start-process}, both
address@hidden and @code{coding-system-for-write}
-affect it.
address@hidden defvar
-
address@hidden inhibit-eol-conversion
-When this variable is address@hidden, no end-of-line conversion is done,
-no matter which coding system is specified. This applies to all the
-Emacs I/O and subprocess primitives, and to the explicit encoding and
-decoding functions (@pxref{Explicit Encoding}).
address@hidden defvar
-
address@hidden Explicit Encoding
address@hidden Explicit Encoding and Decoding
address@hidden encoding in coding systems
address@hidden decoding in coding systems
-
- All the operations that transfer text in and out of Emacs have the
-ability to use a coding system to encode or decode the text.
-You can also explicitly encode and decode text using the functions
-in this section.
-
- The result of encoding, and the input to decoding, are not ordinary
-text. They logically consist of a series of byte values; that is, a
-series of characters whose codes are in the range 0 through 255. In a
-multibyte buffer or string, character codes 128 through 159 are
-represented by multibyte sequences, but this is invisible to Lisp
-programs.
-
- The usual way to read a file into a buffer as a sequence of bytes, so
-you can decode the contents explicitly, is with
address@hidden (@pxref{Reading from Files});
-alternatively, specify a address@hidden @var{rawfile} argument when
-visiting a file with @code{find-file-noselect}. These methods result in
-a unibyte buffer.
-
- The usual way to use the byte sequence that results from explicitly
-encoding text is to copy it to a file or process---for example, to write
-it with @code{write-region} (@pxref{Writing to Files}), and suppress
-encoding by binding @code{coding-system-for-write} to
address@hidden
-
- Here are the functions to perform explicit encoding or decoding. The
-encoding functions produce sequences of bytes; the decoding functions
-are meant to operate on sequences of bytes. All of these functions
-discard text properties.
-
address@hidden Command encode-coding-region start end coding-system
-This command encodes the text from @var{start} to @var{end} according
-to coding system @var{coding-system}. The encoded text replaces the
-original text in the buffer. The result of encoding is logically a
-sequence of bytes, but the buffer remains multibyte if it was multibyte
-before.
-
-This command returns the length of the encoded text.
address@hidden deffn
-
address@hidden encode-coding-string string coding-system &optional nocopy
-This function encodes the text in @var{string} according to coding
-system @var{coding-system}. It returns a new string containing the
-encoded text, except when @var{nocopy} is address@hidden, in which
-case the function may return @var{string} itself if the encoding
-operation is trivial. The result of encoding is a unibyte string.
address@hidden defun
-
address@hidden Command decode-coding-region start end coding-system
-This command decodes the text from @var{start} to @var{end} according
-to coding system @var{coding-system}. The decoded text replaces the
-original text in the buffer. To make explicit decoding useful, the text
-before decoding ought to be a sequence of byte values, but both
-multibyte and unibyte buffers are acceptable.
-
-This command returns the length of the decoded text.
address@hidden deffn
-
address@hidden decode-coding-string string coding-system &optional nocopy
-This function decodes the text in @var{string} according to coding
-system @var{coding-system}. It returns a new string containing the
-decoded text, except when @var{nocopy} is address@hidden, in which
-case the function may return @var{string} itself if the decoding
-operation is trivial. To make explicit decoding useful, the contents
-of @var{string} ought to be a sequence of byte values, but a multibyte
-string is acceptable.
address@hidden defun
-
address@hidden decode-coding-inserted-region from to filename &optional visit
beg end replace
-This function decodes the text from @var{from} to @var{to} as if
-it were being read from file @var{filename} using @code{insert-file-contents}
-using the rest of the arguments provided.
-
-The normal way to use this function is after reading text from a file
-without decoding, if you decide you would rather have decoded it.
-Instead of deleting the text and reading it again, this time with
-decoding, you can call this function.
address@hidden defun
-
address@hidden Terminal I/O Encoding
address@hidden Terminal I/O Encoding
-
- Emacs can decode keyboard input using a coding system, and encode
-terminal output. This is useful for terminals that transmit or display
-text using a particular encoding such as Latin-1. Emacs does not set
address@hidden for encoding or decoding for the
-terminal.
-
address@hidden keyboard-coding-system
-This function returns the coding system that is in use for decoding
-keyboard input---or @code{nil} if no coding system is to be used.
address@hidden defun
-
address@hidden Command set-keyboard-coding-system coding-system
-This command specifies @var{coding-system} as the coding system to
-use for decoding keyboard input. If @var{coding-system} is @code{nil},
-that means do not decode keyboard input.
address@hidden deffn
-
address@hidden terminal-coding-system
-This function returns the coding system that is in use for encoding
-terminal output---or @code{nil} for no encoding.
address@hidden defun
-
address@hidden Command set-terminal-coding-system coding-system
-This command specifies @var{coding-system} as the coding system to use
-for encoding terminal output. If @var{coding-system} is @code{nil},
-that means do not encode terminal output.
address@hidden deffn
-
address@hidden MS-DOS File Types
address@hidden MS-DOS File Types
address@hidden DOS file types
address@hidden MS-DOS file types
address@hidden Windows file types
address@hidden file types on MS-DOS and Windows
address@hidden text files and binary files
address@hidden binary files and text files
-
- On MS-DOS and Microsoft Windows, Emacs guesses the appropriate
-end-of-line conversion for a file by looking at the file's name. This
-feature classifies files as @dfn{text files} and @dfn{binary files}. By
-``binary file'' we mean a file of literal byte values that are not
-necessarily meant to be characters; Emacs does no end-of-line conversion
-and no character code conversion for them. On the other hand, the bytes
-in a text file are intended to represent characters; when you create a
-new file whose name implies that it is a text file, Emacs uses DOS
-end-of-line conversion.
-
address@hidden buffer-file-type
-This variable, automatically buffer-local in each buffer, records the
-file type of the buffer's visited file. When a buffer does not specify
-a coding system with @code{buffer-file-coding-system}, this variable is
-used to determine which coding system to use when writing the contents
-of the buffer. It should be @code{nil} for text, @code{t} for binary.
-If it is @code{t}, the coding system is @code{no-conversion}.
-Otherwise, @code{undecided-dos} is used.
-
-Normally this variable is set by visiting a file; it is set to
address@hidden if the file was visited without any actual conversion.
address@hidden defvar
-
address@hidden file-name-buffer-file-type-alist
-This variable holds an alist for recognizing text and binary files.
-Each element has the form (@var{regexp} . @var{type}), where
address@hidden is matched against the file name, and @var{type} may be
address@hidden for text, @code{t} for binary, or a function to call to
-compute which. If it is a function, then it is called with a single
-argument (the file name) and should return @code{t} or @code{nil}.
-
-When running on MS-DOS or MS-Windows, Emacs checks this alist to decide
-which coding system to use when reading a file. For a text file,
address@hidden is used. For a binary file, @code{no-conversion}
-is used.
-
-If no element in this alist matches a given file name, then
address@hidden says how to treat the file.
address@hidden defopt
-
address@hidden default-buffer-file-type
-This variable says how to handle files for which
address@hidden says nothing about the type.
-
-If this variable is address@hidden, then these files are treated as
-binary: the coding system @code{no-conversion} is used. Otherwise,
-nothing special is done for them---the coding system is deduced solely
-from the file contents, in the usual Emacs fashion.
address@hidden defopt
-
address@hidden Input Methods
address@hidden Input Methods
address@hidden input methods
-
- @dfn{Input methods} provide convenient ways of entering address@hidden
-characters from the keyboard. Unlike coding systems, which translate
address@hidden characters to and from encodings meant to be read by
-programs, input methods provide human-friendly commands. (@xref{Input
-Methods,,, emacs, The GNU Emacs Manual}, for information on how users
-use input methods to enter text.) How to define input methods is not
-yet documented in this manual, but here we describe how to use them.
-
- Each input method has a name, which is currently a string;
-in the future, symbols may also be usable as input method names.
-
address@hidden current-input-method
-This variable holds the name of the input method now active in the
-current buffer. (It automatically becomes local in each buffer when set
-in any fashion.) It is @code{nil} if no input method is active in the
-buffer now.
address@hidden defvar
-
address@hidden default-input-method
-This variable holds the default input method for commands that choose an
-input method. Unlike @code{current-input-method}, this variable is
-normally global.
address@hidden defopt
-
address@hidden Command set-input-method input-method
-This command activates input method @var{input-method} for the current
-buffer. It also sets @code{default-input-method} to @var{input-method}.
-If @var{input-method} is @code{nil}, this command deactivates any input
-method for the current buffer.
address@hidden deffn
-
address@hidden read-input-method-name prompt &optional default inhibit-null
-This function reads an input method name with the minibuffer, prompting
-with @var{prompt}. If @var{default} is address@hidden, that is returned
-by default, if the user enters empty input. However, if
address@hidden is address@hidden, empty input signals an error.
-
-The returned value is a string.
address@hidden defun
-
address@hidden input-method-alist
-This variable defines all the supported input methods.
-Each element defines one input method, and should have the form:
-
address@hidden
-(@var{input-method} @var{language-env} @var{activate-func}
- @var{title} @var{description} @var{args}...)
address@hidden example
-
-Here @var{input-method} is the input method name, a string;
address@hidden is another string, the name of the language
-environment this input method is recommended for. (That serves only for
-documentation purposes.)
-
address@hidden is a function to call to activate this method. The
address@hidden, if any, are passed as arguments to @var{activate-func}. All
-told, the arguments to @var{activate-func} are @var{input-method} and
-the @var{args}.
-
address@hidden is a string to display in the mode line while this method is
-active. @var{description} is a string describing this method and what
-it is good for.
address@hidden defvar
-
- The fundamental interface to input methods is through the
-variable @code{input-method-function}. @xref{Reading One Event},
-and @ref{Invoking the Input Method}.
-
address@hidden Locales
address@hidden Locales
address@hidden locale
-
- POSIX defines a concept of ``locales'' which control which language
-to use in language-related features. These Emacs variables control
-how Emacs interacts with these features.
-
address@hidden locale-coding-system
address@hidden keyboard input decoding on X
-This variable specifies the coding system to use for decoding system
-error messages and---on X Window system only---keyboard input, for
-encoding the format argument to @code{format-time-string}, and for
-decoding the return value of @code{format-time-string}.
address@hidden defvar
-
address@hidden system-messages-locale
-This variable specifies the locale to use for generating system error
-messages. Changing the locale can cause messages to come out in a
-different language or in a different orthography. If the variable is
address@hidden, the locale is specified by environment variables in the
-usual POSIX fashion.
address@hidden defvar
-
address@hidden system-time-locale
-This variable specifies the locale to use for formatting time values.
-Changing the locale can cause messages to appear according to the
-conventions of a different language. If the variable is @code{nil}, the
-locale is specified by environment variables in the usual POSIX fashion.
address@hidden defvar
-
address@hidden locale-info item
-This function returns locale data @var{item} for the current POSIX
-locale, if available. @var{item} should be one of these symbols:
-
address@hidden @code
address@hidden codeset
-Return the character set as a string (locale item @code{CODESET}).
-
address@hidden days
-Return a 7-element vector of day names (locale items
address@hidden through @code{DAY_7});
-
address@hidden months
-Return a 12-element vector of month names (locale items @code{MON_1}
-through @code{MON_12}).
-
address@hidden paper
-Return a list @code{(@var{width} @var{height})} for the default paper
-size measured in millimeters (locale items @code{PAPER_WIDTH} and
address@hidden).
address@hidden table
-
-If the system can't provide the requested information, or if
address@hidden is not one of those symbols, the value is @code{nil}. All
-strings in the return value are decoded using
address@hidden @xref{Locales,,, libc, The GNU Libc Manual},
-for more information about locales and locale items.
address@hidden defun
-
address@hidden
- arch-tag: be705bf8-941b-4c35-84fc-ad7d20ddb7cb
address@hidden ignore
- [Emacs-diffs] Changes to nonascii.texi,
Glenn Morris <=