This is the file cjk-enc.txt of the CJK macro package ver. 4.8.5
(16-Oct-2021).

cjk-enc.el
----------

Mule, the multilingual Emacs, is one of the most powerful editors available
for Unix systems like Linux. It is capable to edit and display texts which
are, among other scripts, written in various CJK languages; as an example
you can have traditional and simplified Chinese at the same time. Mule is
distributed under the GNU Public License; it is now integrated into the
source code emacs 20.

The CJK package enables LaTeX to do the same (with some restrictions, see
below), but the interface is different. Mule uses additional bits internally
to store the encoding of a character, whereas the CJK package needs \CJKenc
macros to select encodings.

Now enters cjk-enc.el . This small output filter for Mule (written in Lisp)
converts text as entered in Mule into a form TeX can understand. Double-byte
encodings which can be processed by CJK are usually converted into EUC form
preceded by \CJKenc{...} macros, single-byte encodings (Latin-1, etc.) into
equivalent LaTeX 2e macros (e.g., Latin-1 character 0xC4 (umlaut A) into
\"A). Some of these macros are undefined by default in standard LaTeX 2e
because CM or EC fonts have no characters for it. Vietnamese, Cyrillic
scripts, Modern Greek, and Thai are also supported (see below).

cjk-enc.el comes in two versions.

  .  An old version for Mule 2.3 with limited capabilities since it is no
     longer supported (but updated if necessary).

  .  A new version with enhanced commands which works with emacs versions
     >= 20.3 and xemacs versions >= 21.1 (the latter without Thai support).

Support for emacs versions < 20.3 has been dropped. Please upgrade. In the
following, `Mule' is used for all emacs flavours.


Installation
------------

To load cjk-enc.el into Mule, put the following line into your .emacs file:

    (load-library "cjk-enc")

this assumes that cjk-enc.el is in a directory searched by Mule. A good
place for it is the site-lisp subdirectory (e.g.,
/usr/local/share/emacs/site-lisp).

After loading, a new (output) encoding scheme is defined: `*cjk-coding*'.
[This is called `cjk-coding' under emacs 20---Please note further that the
 prefix for Mule commands has changed to `C-x RET' for emacs 20 instead of
 `C-x C-k'.]

Note: `*cjk-coding*' (`cjk-coding') can't be used to save documents! It
      is intended only to create the *.cjk file which is then directly
      processed by LaTeX.


Usage (LaTeX 2e part)
---------------------

A sample of a multilingual document (muletest.{tex,cjk,dvi,pdf}) can be
found in the examples subdirectory (only the TEX file is in the src package
of CJK, the other files are in the doc package).

European languages based on the Latin script:

    Simply write your documents! Characters like `u umlaut' or `c hacek' are
    converted into LaTeX 2e macros. You don't need to write "u or something
    else (nevertheless it's possible). It is recommended to use LaTeX 2e's
    T1 font encoding scheme to have a) most of the European diacritics
    available and b) correct hyphenation for accented characters.

    The lower half of JIS X 0201 is treated similarly.

    Note that the default CM fonts of LaTeX are OT1 encoded. You should
    rather use the EC fonts which are based on T1 (or virtual T1 fonts
    mapped onto OT1).

    For correct hyphenation you still have to change languages, thus a
    system like Babel should be used additionally.

CJK languages:

    Don't start a CJK (or CJK*) environment! cjk-enc.el does this
    automatically for you at the `\begin{document}' command. It also inserts
    \CJKspace and \CJKnospace commands (\CJKspace for Korean, \CJKnospace
    for all other CJK scripts; but see the section `Problems' below also).

    In CJK.enc the default font family for all encodings is `song' (except
    for Korean Hangul where it is `mj'). Two commands are available to
    change the CJK font encoding and family in combination with cjk-enc.el
    (see CJK.txt and commands.txt for a detailed description):

        \CJKencfamily[<fontencoding>]{<encoding>}{<family>}
            Change family for a certain encoding (and fontencoding).

        \CJKfontenc{<encoding>}{<fontencoding>} 
             Change fontencoding for a certain encoding.

    The second command is primarily for users who use Japanese DNP fonts
    (see the Japanese documentation subdirectory for further details) or
    Korean HLaTeX fonts.

    For the upper half of JIS X 0201 encoding, the katakana range of the
    SJIS encoding of the CJK package is used.

Vietnamese:

    Vietnamese uses accented characters not contained in EC or CM fonts. To
    assure proper kerning you must explicitly activate T5 font encoding
    (this can't be done automatically) to access a Vietnamese font.

    The VnTeX bundle contains Vietnamese fonts and support files; it also
    defines T5 encoding. It is available from http://vntex.sf.net.
    (Note that the now obsolete vncmr package is no longer supported.)

Russian and other languages using the cyrillic script:

    Cyrillic LaTeX encodings (T2A, T2B, T2C, and X2) are now supported
    within the LaTeX 2e distribution (starting with version 1998/12/01).
    Cyrillic fonts and auxiliary files supporting these encodings are
    available at CTAN from fonts/cyrillic and macros/latex/contrib/t2); most
    TeX distributions already come with Cyrillic fonts installed.

    The current implemention needs a lot of temporary disk space for
    Cyrillic scripts (e.g., a 100 kByte document written only with Cyrillic
    letters has an intermediate output file of about 800 kByte). On the
    other hand, it is still possible to recognize the Cyrillic characters
    name macros in the log file in case of error messages---if I used the
    shortest possible representation, only numbers would be visible, and the
    size of the intermediate output file would still have 500 kByte...

    You must explicitly activate one of the T2* (or X2) encodings for
    Cyrillic. Russian needs T2A.

Greek:

    You must use the LGR encoding and fonts as defined in the Babel package:
    ISO-8859-7 characters are mapped back to ASCII characters which are then
    displayed as Greek characters, using the ligature mechanism extensively.

Thai:

    It is implemented only in the emacs 20.3 version of cjk-enc.el. Instead
    of using an external program, Ken'ichi Handa has written thai-word.el
    which implements the word-breaking algorithm in Lisp, based on the the
    C-TTeX package version 1.15 written by Vuthichai Ampornaramveth
    <vuthi@ctrl.titech.ac.jp>. `thai.sty' is still very rudimentary---any
    improvements are welcome.

    The used encoding is C90 (this is the only case where you have to
    specify a `C' encoding directly, either by using the `thaicjk' language
    for Babel or by saying `\DeclareFontEncoding{C90}{}{}' in the preamble);
    the default fonts specified in c90gar.fd and c90nrsr.fd are taken from
    the thailatex package, which can be found at

      http://linux.thai.net/plone/TLWG/thailatex

    You should use version 0.3.5.1 or newer. Note that this package is not
    compatible with CJK; neither its metric files nor its LaTeX support
    files should be used. Please read the file thaifont.txt for details how
    to install the fonts.

    Whitespace between Thai characters are always respected; newlines
    together with trailing and leading whitespace are not by default. Use
    \Thaispace to make trailing and leading whitespace respected also (the
    opposite command is \Thainospace). Note that the space width of the Thai
    font (which is usually larger than for a Roman font) is used for
    whitespace between Thai words:

      Thai Thai
      Thai

    is approximately translated to

      {\thaifont Thai Thai\nospaces
       Thai}

    (if \Thainospace is active), whereas

      Thai\ Thai\
      Thai

    is approximately translated to

     {\thaifont Thai}{\romanfont\ }{\thaifont Thai}{\romanfont\ }
     {\thaifont Thai}

    To improve appearance, \Thaiglue (which is defined in MULEenc.sty) is
    used as intercharacter glue; this value can be modified similarly to
    \CJKglue.


Usage (Mule part)
-----------------

Simply load your document into Mule and call cjk-write-file (which is
defined in cjk-enc.el) to create a preprocessed file. For most files this
file's name is formed by replacing the extension with `.cjk'. However,
BibTeX files are given the extension `-cjk.bib' because the BibTeX program
requires `.bib' as the extension. This also avoids conflicts with the CJK
file produced by a LaTeX file by the same name. Because of this you should
use the command \CJKbibliography{foo} in your LaTeX source file (which
finally expands to foo-cjk.bib). A similar macro is \CJKinclude{bar} which
expands to `bar.cjk' instead of bar.tex. Finally, you can say
\CJKinput{foo.bar} to input file `foo.bar'; if the file name has no
extension, `cjk' is appended: \CJKinput{foo} loads `foo.cjk'.

cjk-write-file is the only user function provided by cjk-enc.el for
Mule 2.3.

If you want to process a file which includes some other files, use the
function cjk-write-all-files in combination with \CJKinclude, \CJKinput, and
\CJKbibliography. If used interactively, you have to supply a file name
which is then scanned for occurrences of \CJKinclude, \CJKinput, and
\CJKbibliography; all files found plus the master file are converted.

Example:

  `a.tex' contains:

    \CJKenc{Bg5}
    Chinese text

  `b.tex' contains:

    \CJKenc{JIS}
    Japanese text

  `c.tex' contains:

    \CJKenc{UTF8}
    Some Unicode text

  `master.tex' can now include the files as follows:

    Some Korean text

    \CJKinput{a}
    \input{b}
    \input{c}

  Calling cjk-write-all-files automatically converts `master.tex' and
  `a.tex'.

The functions batch-cjk-write-file and batch-force-write-file are intended
to be used in Makefiles; please read the function documentation for more
details.

It is recommended that you assign cjk-write-file or cjk-write-all-files to a
key (e.g., with global-set-key) in your `.emacs' configuration file.


Unicode encoding
................

Note that the forthcoming Emacs 22 has no native Unicode support. Instead,
Unicode encoded date is mapped onto the internal character sets of Emacs;
this process heavily depends on the selected (Emacs) language environment.
For example, if you select `Chinese-BIG5', Emacs first tries to map Unicode
characters to Big 5. If that fails, it tries the GB 2312 character set, then
KS X 1001, and so on. To get typographically satisfying output you would
need identical font shapes for different CJK encodings, a very unlikely
situation.

For this reason it is strongly recommended to *not* use data files encoded
in UTF-8 with cjk-enc.el. Instead, UTF-8 should be directly handled by a CJK
environment (i.e., `\begin{CJK}{UTF8}{...}').


Usage with AUC TeX
------------------

Append the data between >>> and <<< to your .emacs file to have special CJK
support within AUC TeX:


>>>

  (defun TeX-run-CJK-LaTeX (name command file)
    "Create a process for NAME using COMMAND to format FILE with CJK/LaTeX."

; use next code line for Mule instead of the (balanced) expression
; containing `cjk-write-all-files'
; -- no multifile document support!
;   (cjk-write-file)

    (cjk-write-all-files (concat (TeX-master-directory)
                                 (file-name-nondirectory file)
                                 ".tex"))
    (TeX-run-LaTeX name command file))

  ;; replace the error source file `*.cjk' with `*.tex' (and `*-cjk.bib'
  ;; with `*.bib'), then C-c ` can be used as usual.

  (add-hook 'TeX-translate-location-hook
            '(lambda ()
               (if (string-match "\\(.*\\)\.cjk$" file)
                   (setq file
                         (concat
                           (substring file
                                      (match-beginning 1)
                                      (match-end 1))
                           ".tex"))
                 (if (string-match "\\(.*\\)-cjk\.bib$" file)
                     (setq file
                           (concat
                             (substring file
                                        (match-beginning 1)
                                        (match-end 1))
                             ".bib"))))))

  (require 'tex)
  (add-to-list 'TeX-command-list  
    '("CJKLaTeX" "%l '\\nonstopmode\\input{%s.cjk}'" TeX-run-CJK-LaTeX nil t))

<<<


To process a CJK document with AUC TeX use C-c C-c on your LaTeX source file
and select CJKLaTeX as the formatting command. It also works with multiple
files; only modified files are converted (again).

Note that only the master file is processed with cjk-enc and scanned for
\CJKinclude and \CJKinput!

If you mainly write text in Japanese or Chinese, consider the use of
cjkspace.el or cjktilde.el for inserting a tilde character (which has been
redefined to a shibuaki space) if you hit the space key. Please read the
documentation in the two files for differences. cjkspace.el works with
AUC TeX only, cjktilde.el works in every mode.

In case you use an Emacs input method (quail) for your Asian language
(contrary to an external input method provided by the operating system), you
can add `rules' with the following code added to your .emacs file; the
special space handling is then active only when the corresponding input
method is active too.

  (add-hook 'quail-activate-hook
            (function
             (lambda () 
               (if (equal (quail-name) "chinese-py-punct-b5")
                   (progn
                     (quail-defrule " " "~")
                     (quail-defrule "  " " "))))))

Replace `chinese-py-punct-b5' with your favourite input encoding. In case
you use more than one input method, repeat the above lisp code for each
method.


Technical notes
---------------

cjk-enc.el loads MULEenc.sty or CJK.sty in the first output line which
contains all needed definitions for LaTeX 2e.

To assure working in verbatim environments, \CJKenc and the LaTeX 2e macros
are not output directly. The active character 0x7F is used to output
\CJKenc, \CJKspace, Latin characters, etc.

CNS 1-CNS 7 and JIS2 encoded characters are output as \CJKchar macros. The
reason for this choice is the infrequency of CNS and JIS2 characters in
normal text. Since \CJKchar does not select a new binding this macro is
executed faster for single CNS and JIS2 characters.


Problems and Tips
-----------------

. cjk-enc.el starts a CJK environment only if it finds at least one CJK
  character in the master file; this character can appear in a comment also.
  Example:

    % some Chinese text in this comment
    \CJKinput{a}
    \CJKbibliography{b}

. If you need some CJK processing in the preamble you must start a CJK
  environment there manually because cjk-enc.el uses the \AtBeginDocument
  hook for its commands. This interferes with the \CJKspace/\CJKnospace
  insertion mechanism of cjk-enc.el because the Lisp code always assumes a
  single, global CJK environment. A similar problem exists if you start a
  new language in a comment. To overcome this, simply insert a \CJKspace or
  \CJKnospace command (whatever appropriate) right after the
  `\begin{document}' macro to synchronize again with cjk-enc.el .

  Example:

    \documentclass{article}

    \begin{CJK*}{}{}
      some Japanese macro stuff
    \end{CJK*}

    \begin{document}
    \CJKnospace
    more Japanese text
    ...

. Another consequence of the \CJKspace/\CJKnospace insertion mechanism of
  cjk-enc.el is that in cases like

    Latin_text Chinese_text\ Latin_text

  you can't omit the final `\ ' after the Chinese phrase---only for Korean
  words it is not necessary to use a (protected) space.

. Usually, Emacs can automatically recognize the encoding of a given file
  (e.g., using a language environment or setting `file-coding-system-alist';
  please read the chapter `Recognizing Coding Systems' in the emacs info
  files for further details). But sometimes this fails (e.g., to find out
  whether a text is in latin-1 or in, say, latin-3 is impossible), and you
  have to use a file variable to define the encoding.

  Here an example how to specify `Big 5' encoding for a TeX input file (the
  following lines are to be inserted at the very end):

    % Local Variables:
    % coding: big5
    % End:

  If AUCTeX already has created local variables like `TeX-master', simply
  add the line `coding: big5' and you are done.

. Another useful local variable for AUCTeX is `TeX-command-default':

    % Local Variables:
    % TeX-command-default: "CJKLaTeX"
    % End:

  selects `CJKLaTeX' as the default command if you type `C-c C-c'.


---End of cjk-enc.txt---