path: root/runtime/doc/mbyte.txt

*mbyte.txt*     Nvim


		  VIM REFERENCE MANUAL	  by Bram Moolenaar et al.


Multi-byte support				*multibyte* *multi-byte*
						*Chinese* *Japanese* *Korean*
This is about editing text in languages which have many characters that can
not be represented using one byte (one octet).  Examples are Chinese, Japanese
and Korean.  Unicode is also covered here.

For an introduction to the most common features, see |usr_45.txt| in the user
manual.
For changing the language of messages and menus see |mlang.txt|.

                                      Type |gO| to see the table of contents.

==============================================================================
Getting started						*mbyte-first*

This is a summary of the multibyte features in Vim.  If you are lucky it works
as described and you can start using Vim without much trouble.  If something
doesn't work you will have to read the rest.  Don't be surprised if it takes
quite a bit of work and experimenting to make Vim use all the multi-byte
features.  Unfortunately, every system has its own way to deal with multibyte
languages and it is quite complicated.


LOCALE

First of all, you must make sure your current locale is set correctly.  If
your system has been installed to use the language, it probably works right
away.  If not, you can often make it work by setting the $LANG environment
variable in your shell: >

	setenv LANG ja_JP.EUC

Unfortunately, the name of the locale depends on your system.  Japanese might
also be called "ja_JP.EUCjp" or just "ja".  To see what is currently used: >

	:language

To change the locale inside Vim use: >

	:language ja_JP.EUC

Vim will give an error message if this doesn't work.  This is a good way to
experiment and find the locale name you want to use.  But it's always better
to set the locale in the shell, so that it is used right from the start.

See |mbyte-locale| for details.


ENCODING

Nvim always uses UTF-8 internally. Thus 'encoding' option is always set
to "utf-8" and cannot be changed.

All the text that is used inside Vim will be in UTF-8. Not only the text in
the buffers, but also in registers, variables, etc.

You can edit files in different encodings than UTF-8.  Nvim
will convert the file when you read it and convert it back when you write it.
See 'fileencoding', 'fileencodings' and |++enc|.


DISPLAY AND FONTS

If you are working in a terminal (emulator) you must make sure it accepts
UTF-8, the encoding which Vim is working with. Otherwise only ASCII can
be displayed and edited correctly.

For the GUI you must select fonts that work with UTF-8.  This
is the difficult part.  It depends on the system you are using, the locale and
a few other things.

For X11 you can set the 'guifontset' option to a list of fonts that together
cover the characters that are used.  Example for Korean: >

	:set guifontset=k12,r12

Alternatively, you can set 'guifont' and 'guifontwide'.  'guifont' is used for
the single-width characters, 'guifontwide' for the double-width characters.
Thus the 'guifontwide' font must be exactly twice as wide as 'guifont'.
Example for UTF-8: >

	:set guifont=-misc-fixed-medium-r-normal-*-18-120-100-100-c-90-iso10646-1
	:set guifontwide=-misc-fixed-medium-r-normal-*-18-120-100-100-c-180-iso10646-1

You can also set 'guifont' alone, Vim will try to find a matching
'guifontwide' for you.


INPUT

There are several ways to enter multi-byte characters:
- For X11 XIM can be used.  See |XIM|.
- For MS-Windows IME can be used.  See |IME|.
- For all systems keymaps can be used.  See |mbyte-keymap|.

The options 'iminsert', 'imsearch' and 'imcmdline' can be used to chose
the different input methods or disable them temporarily.

==============================================================================
Locale							*mbyte-locale*

The easiest setup is when your whole system uses the locale you want to work
in.  But it's also possible to set the locale for one shell you are working
in, or just use a certain locale inside Vim.


WHAT IS A LOCALE?					*locale*

There are many of languages in the world.  And there are different cultures
and environments at least as much as the number of languages.	A linguistic
environment corresponding to an area is called "locale".  This includes
information about the used language, the charset, collating order for sorting,
date format, currency format and so on.  For Vim only the language and charset
really matter.

You can only use a locale if your system has support for it.  Some systems
have only a few locales, especially in the USA.  The language which you want
to use may not be on your system.  In that case you might be able to install
it as an extra package.  Check your system documentation for how to do that.

The location in which the locales are installed varies from system to system.
For example, "/usr/share/locale" or "/usr/lib/locale".  See your system's
setlocale() man page.

Looking in these directories will show you the exact name of each locale.
Mostly upper/lowercase matters, thus "ja_JP.EUC" and "ja_jp.euc" are
different.  Some systems have a locale.alias file, which allows translation
from a short name like "nl" to the full name "nl_NL.ISO_8859-1".

Note that X-windows has its own locale stuff.  And unfortunately uses locale
names different from what is used elsewhere.  This is confusing!  For Vim it
matters what the setlocale() function uses, which is generally NOT the
X-windows stuff.  You might have to do some experiments to find out what
really works.

							*locale-name*
The (simplified) format of |locale| name is:

	language
or	language_territory
or	language_territory.codeset

Territory means the country (or part of it), codeset means the |charset|.  For
example, the locale name "ja_JP.eucJP" means:
	ja	the language is Japanese
	JP	the country is Japan
	eucJP	the codeset is EUC-JP
But it also could be "ja", "ja_JP.EUC", "ja_JP.ujis", etc.  And unfortunately,
the locale name for a specific language, territory and codeset is not unified
and depends on your system.

Examples of locale name:
    charset	    language		  locale name ~
    GB2312	    Chinese (simplified)  zh_CN.EUC, zh_CN.GB2312
    Big5	    Chinese (traditional) zh_TW.BIG5, zh_TW.Big5
    CNS-11643	    Chinese (traditional) zh_TW
    EUC-JP	    Japanese		  ja, ja_JP.EUC, ja_JP.ujis, ja_JP.eucJP
    Shift_JIS	    Japanese		  ja_JP.SJIS, ja_JP.Shift_JIS
    EUC-KR	    Korean		  ko, ko_KR.EUC


USING A LOCALE

To start using a locale for the whole system, see the documentation of your
system.  Mostly you need to set it in a configuration file in "/etc".

To use a locale in a shell, set the $LANG environment value.  When you want to
use Korean and the |locale| name is "ko", do this:

    sh:    export LANG=ko
    csh:   setenv LANG ko

You can put this in your ~/.profile or ~/.cshrc file to always use it.

To use a locale in Vim only, use the |:language| command: >

	:language ko

Put this in your |init.vim| file to use it always.

Or specify $LANG when starting Vim:

   sh:    LANG=ko vim {vim-arguments}
   csh:	  env LANG=ko vim {vim-arguments}

You could make a small shell script for this.

==============================================================================
Encoding				*mbyte-encoding*

In Nvim UTF-8 is always used internally to encode characters.
 This applies to all the places where text is used, including buffers (files
 loaded into memory), registers and variables.

							*charset* *codeset*
Charset is another name for encoding.  There are subtle differences, but these
don't matter when using Vim.  "codeset" is another similar name.

Each character is encoded as one or more bytes.  When all characters are
encoded with one byte, we call this a single-byte encoding.  The most often
used one is called "latin1".  This limits the number of characters to 256.
Some of these are control characters, thus even fewer can be used for text.

When some characters use two or more bytes, we call this a multi-byte
encoding.  This allows using much more than 256 characters, which is required
for most East Asian languages.

Most multi-byte encodings use one byte for the first 127 characters.  These
are equal to ASCII, which makes it easy to exchange plain-ASCII text, no
matter what language is used.  Thus you might see the right text even when the
encoding was set wrong.

							*encoding-names*
Vim can edit files in different character encodings.  There are three major groups:

1   8bit	Single-byte encodings, 256 different characters.  Mostly used
		in USA and Europe.  Example: ISO-8859-1 (Latin1).  All
		characters occupy one screen cell only.

2   2byte	Double-byte encodings, over 10000 different characters.
		Mostly used in Asian countries.  Example: euc-kr (Korean)
		The number of screen cells is equal to the number of bytes
		(except for euc-jp when the first byte is 0x8e).

u   Unicode	Universal encoding, can replace all others.  ISO 10646.
		Millions of different characters.  Example: UTF-8.  The
		relation between bytes and screen cells is complex.

Only UTF-8 is used by Vim internally.  But files in other
encodings can be edited by using conversion, see 'fileencoding'.

Recognized 'fileencoding' values include:		*encoding-values*
1   latin1	8-bit characters (ISO 8859-1, also used for cp1252)
1   iso-8859-n	ISO_8859 variant (n = 2 to 15)
1   koi8-r	Russian
1   koi8-u	Ukrainian
1   macroman    MacRoman (Macintosh encoding)
1   8bit-{name} any 8-bit encoding (Vim specific name)
1   cp437	similar to iso-8859-1
1   cp737	similar to iso-8859-7
1   cp775	Baltic
1   cp850	similar to iso-8859-4
1   cp852	similar to iso-8859-1
1   cp855	similar to iso-8859-2
1   cp857	similar to iso-8859-5
1   cp860	similar to iso-8859-9
1   cp861	similar to iso-8859-1
1   cp862	similar to iso-8859-1
1   cp863	similar to iso-8859-8
1   cp865	similar to iso-8859-1
1   cp866	similar to iso-8859-5
1   cp869	similar to iso-8859-7
1   cp874	Thai
1   cp1250	Czech, Polish, etc.
1   cp1251	Cyrillic
1   cp1253	Greek
1   cp1254	Turkish
1   cp1255	Hebrew
1   cp1256	Arabic
1   cp1257	Baltic
1   cp1258	Vietnamese
1   cp{number}	MS-Windows: any installed single-byte codepage
2   cp932	Japanese (Windows only)
2   euc-jp	Japanese (Unix only)
2   sjis	Japanese (Unix only)
2   cp949	Korean (Unix and Windows)
2   euc-kr	Korean (Unix only)
2   cp936	simplified Chinese (Windows only)
2   euc-cn	simplified Chinese (Unix only)
2   cp950	traditional Chinese (on Unix alias for big5)
2   big5	traditional Chinese (on Windows alias for cp950)
2   euc-tw	traditional Chinese (Unix only)
2   2byte-{name} Unix: any double-byte encoding (Vim specific name)
2   cp{number}	MS-Windows: any installed double-byte codepage
u   utf-8	32 bit UTF-8 encoded Unicode (ISO/IEC 10646-1)
u   ucs-2	16 bit UCS-2 encoded Unicode (ISO/IEC 10646-1)
u   ucs-2le	like ucs-2, little endian
u   utf-16	ucs-2 extended with double-words for more characters
u   utf-16le	like utf-16, little endian
u   ucs-4	32 bit UCS-4 encoded Unicode (ISO/IEC 10646-1)
u   ucs-4le	like ucs-4, little endian

The {name} can be any encoding name that your system supports.  It is passed
to iconv() to convert between UTF-8 and the encoding of the file.
For MS-Windows "cp{number}" means using codepage {number}.
Examples: >
		:set fileencoding=8bit-cp1252
		:set fileencoding=2byte-cp932

The MS-Windows codepage 1252 is very similar to latin1.  For practical reasons
the same encoding is used and it's called latin1.  'isprint' can be used to
display the characters 0x80 - 0xA0 or not.

Several aliases can be used, they are translated to one of the names above.
An incomplete list:

1   ansi	same as latin1 (obsolete, for backward compatibility)
2   japan	Japanese: on Unix "euc-jp", on MS-Windows cp932
2   korea	Korean: on Unix "euc-kr", on MS-Windows cp949
2   prc		simplified Chinese: on Unix "euc-cn", on MS-Windows cp936
2   chinese     same as "prc"
2   taiwan	traditional Chinese: on Unix "euc-tw", on MS-Windows cp950
u   utf8	same as utf-8
u   unicode	same as ucs-2
u   ucs2be	same as ucs-2 (big endian)
u   ucs-2be	same as ucs-2 (big endian)
u   ucs-4be	same as ucs-4 (big endian)
u   utf-32	same as ucs-4
u   utf-32le	same as ucs-4le
    default     the encoding of the current locale.

For the UCS codes the byte order matters.  This is tricky, use UTF-8 whenever
you can.  The default is to use big-endian (most significant byte comes
first):
	    name	bytes		char ~
	    ucs-2	      11 22	    1122
	    ucs-2le	      22 11	    1122
	    ucs-4	11 22 33 44	11223344
	    ucs-4le	44 33 22 11	11223344

On MS-Windows systems you often want to use "ucs-2le", because it uses little
endian UCS-2.

There are a few encodings which are similar, but not exactly the same.  Vim
treats them as if they were different encodings, so that conversion will be
done when needed.  You might want to use the similar name to avoid conversion
or when conversion is not possible:

	cp932, shift-jis, sjis
	cp936, euc-cn

CONVERSION						*charset-conversion*

Vim will automatically convert from one to another encoding in several places:
- When reading a file and 'fileencoding' is different from "utf-8"
- When writing a file and 'fileencoding' is different from "utf-8"
- When displaying messages and the encoding used for LC_MESSAGES differs from
  "utf-8" (requires a gettext version that supports this).
- When reading a Vim script where |:scriptencoding| is different from
  "utf-8".
Most of these require the |+iconv| feature.  Conversion for reading and
writing files may also be specified with the 'charconvert' option.

Useful utilities for converting the charset:
    All:	    iconv
	GNU iconv can convert most encodings.  Unicode is used as the
	intermediate encoding, which allows conversion from and to all other
	encodings.  See http://www.gnu.org/directory/libiconv.html.

    Japanese:	    nkf
	Nkf is "Network Kanji code conversion Filter".  One of the most unique
	facility of nkf is the guess of the input Kanji code.  So, you don't
	need to know what the inputting file's |charset| is.  When convert to
	EUC-JP from ISO-2022-JP or Shift_JIS, simply do the following command
	in Vim:
	    :%!nkf -e
	Nkf can be found at:
	http://www.sfc.wide.ad.jp/~max/FreeBSD/ports/distfiles/nkf-1.62.tar.gz

    Chinese:	    hc
	Hc is "Hanzi Converter".  Hc convert a GB file to a Big5 file, or Big5
	file to GB file.  Hc can be found at:
	ftp://ftp.cuhk.hk/pub/chinese/ifcss/software/unix/convert/hc-30.tar.gz

    Korean:	    hmconv
	Hmconv is Korean code conversion utility especially for E-mail.  It can
	convert between EUC-KR and ISO-2022-KR.  Hmconv can be found at:
	ftp://ftp.kaist.ac.kr/pub/hangul/code/hmconv/

    Multilingual:   lv
	Lv is a Powerful Multilingual File Viewer.  And it can be worked as
	|charset| converter.  Supported |charset|: ISO-2022-CN, ISO-2022-JP,
	ISO-2022-KR, EUC-CN, EUC-JP, EUC-KR, EUC-TW, UTF-7, UTF-8, ISO-8859
	series, Shift_JIS, Big5 and HZ.  Lv can be found at:
	http://www.ff.iij4u.or.jp/~nrt/lv/index.html


							*mbyte-conversion*
When reading and writing files in an encoding different from "utf-8",
conversion needs to be done.  These conversions are supported:
- All conversions between Latin-1 (ISO-8859-1), UTF-8, UCS-2 and UCS-4 are
  handled internally.
- For MS-Windows, conversion from and
  to any codepage should work.
- Conversion specified with 'charconvert'
- Conversion with the iconv library, if it is available.
	Old versions of GNU iconv() may cause the conversion to fail (they
	request a very large buffer, more than Vim is willing to provide).
	Try getting another iconv() implementation.

							*iconv-dynamic*
On MS-Windows Vim can be compiled with the |+iconv/dyn| feature.  This means
Vim will search for the "iconv.dll" and "libiconv.dll" libraries.  When
neither of them can be found Vim will still work but some conversions won't be
possible.

==============================================================================
Fonts on X11						*mbyte-fonts-X11*

Unfortunately, using fonts in X11 is complicated.  The name of a single-byte
font is a long string.  For multi-byte fonts we need several of these...

First of all, Vim only accepts fixed-width fonts for displaying text.  You
cannot use proportionally spaced fonts.  This excludes many of the available
(and nicer looking) fonts.  However, for menus and tooltips any font can be
used.

Note that Display and Input are independent.  It is possible to see your
language even though you have no input method for it.

You should get a default font for menus and tooltips that works, but it might
be ugly.  Read the following to find out how to select a better font.


X LOGICAL FONT DESCRIPTION (XLFD)
							*XLFD*
XLFD is the X font name and contains the information about the font size,
charset, etc.  The name is in this format:

FOUNDRY-FAMILY-WEIGHT-SLANT-WIDTH-STYLE-PIXEL-POINT-X-Y-SPACE-AVE-CR-CE

Each field means:

- FOUNDRY:  FOUNDRY field.  The company that created the font.
- FAMILY:   FAMILY_NAME field.  Basic font family name.  (helvetica, gothic,
	    times, etc)
- WEIGHT:   WEIGHT_NAME field.  How thick the letters are.  (light, medium,
	    bold, etc)
- SLANT:    SLANT field.
		r:  Roman (no slant)
		i:  Italic
		o:  Oblique
		ri: Reverse Italic
		ro: Reverse Oblique
		ot: Other
		number:	Scaled font
- WIDTH:    SETWIDTH_NAME field.  Width of characters.  (normal, condensed,
	    narrow, double wide)
- STYLE:    ADD_STYLE_NAME field.  Extra info to describe font.  (Serif, Sans
	    Serif, Informal, Decorated, etc)
- PIXEL:    PIXEL_SIZE field.  Height, in pixels, of characters.
- POINT:    POINT_SIZE field.  Ten times height of characters in points.
- X:	    RESOLUTION_X field.  X resolution (dots per inch).
- Y:	    RESOLUTION_Y field.  Y resolution (dots per inch).
- SPACE:    SPACING field.
		p:  Proportional
		m:  Monospaced
		c:  CharCell
- AVE:	    AVERAGE_WIDTH field.  Ten times average width in pixels.
- CR:	    CHARSET_REGISTRY field.  The name of the charset group.
- CE:	    CHARSET_ENCODING field.  The rest of the charset name.  For some
	    charsets, such as JIS X 0208, if this field is 0, code points has
	    the same value as GL, and GR if 1.

For example, in case of a 16 dots font corresponding to JIS X 0208, it is
written like:
    -misc-fixed-medium-r-normal--16-110-100-100-c-160-jisx0208.1990-0


X FONTSET
						*fontset* *xfontset*
A single-byte charset is typically associated with one font.  For multi-byte
charsets a combination of fonts is often used.  This means that one group of
characters are used from one font and another group from another font (which
might be double wide).  This collection of fonts is called a fontset.

Which fonts are required in a fontset depends on the current locale.  X
windows maintains a table of which groups of characters are required for a
locale.  You have to specify all the fonts that a locale requires in the
'guifontset' option.

NOTE: The fontset always uses the current locale, even though 'encoding' may
be set to use a different charset.  In that situation you might want to use
'guifont' and 'guifontwide' instead of 'guifontset'.

Example:
    |charset| language		    "groups of characters" ~
    GB2312    Chinese (simplified)  ISO-8859-1 and GB 2312
    Big5      Chinese (traditional) ISO-8859-1 and Big5
    CNS-11643 Chinese (traditional) ISO-8859-1, CNS 11643-1 and CNS 11643-2
    EUC-JP    Japanese		    JIS X 0201 and JIS X 0208
    EUC-KR    Korean		    ISO-8859-1 and KS C 5601 (KS X 1001)

You can search for fonts using the xlsfonts command.  For example, when you're
searching for a font for KS C 5601: >
    xlsfonts | grep ksc5601

This is complicated and confusing.  You might want to consult the X-Windows
documentation if there is something you don't understand.

						*base_font_name_list*
When you have found the names of the fonts you want to use, you need to set
the 'guifontset' option.  You specify the list by concatenating the font names
and putting a comma in between them.

For example, when you use the ja_JP.eucJP locale, this requires JIS X 0201
and JIS X 0208.  You could supply a list of fonts that explicitly specifies
the charsets, like: >

 :set guifontset=-misc-fixed-medium-r-normal--14-130-75-75-c-140-jisx0208.1983-0,
	\-misc-fixed-medium-r-normal--14-130-75-75-c-70-jisx0201.1976-0

Alternatively, you can supply a base font name list that omits the c