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;;; mule-cmds.el --- Commands for mulitilingual environment

;; Copyright (C) 1995 Electrotechnical Laboratory, JAPAN.
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;; Licensed to the Free Software Foundation.
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;; Copyright (C) 2000 Free Software Foundation, Inc.
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;; Keywords: mule, multilingual

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
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;;; Code:

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(eval-when-compile (defvar dos-codepage))

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;;; MULE related key bindings and menus.

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(defvar mule-keymap (make-sparse-keymap)
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  "Keymap for Mule (Multilingual environment) specific commands.")
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;; Keep "C-x C-m ..." for mule specific commands.
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(define-key ctl-x-map "\C-m" mule-keymap)
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(define-key mule-keymap "f" 'set-buffer-file-coding-system)
(define-key mule-keymap "t" 'set-terminal-coding-system)
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(define-key mule-keymap "k" 'set-keyboard-coding-system)
(define-key mule-keymap "p" 'set-buffer-process-coding-system)
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(define-key mule-keymap "x" 'set-selection-coding-system)
(define-key mule-keymap "X" 'set-next-selection-coding-system)
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(define-key mule-keymap "\C-\\" 'set-input-method)
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(define-key mule-keymap "c" 'universal-coding-system-argument)
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(define-key mule-keymap "l" 'set-language-environment)
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(define-key help-map "\C-L" 'describe-language-environment)
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(define-key help-map "L" 'describe-language-environment)
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(define-key help-map "\C-\\" 'describe-input-method)
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(define-key help-map "I" 'describe-input-method)
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(define-key help-map "C" 'describe-coding-system)
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(define-key help-map "h" 'view-hello-file)

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(defvar mule-menu-keymap
  (make-sparse-keymap "Mule (Multilingual Environment)")
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  "Keymap for Mule (Multilingual environment) menu specific commands.")
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(defvar describe-language-environment-map
  (make-sparse-keymap "Describe Language Environment"))
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(defvar setup-language-environment-map
  (make-sparse-keymap "Set Language Environment"))
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(defvar set-coding-system-map
  (make-sparse-keymap "Set Coding System"))
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(define-key-after mule-menu-keymap [set-language-environment]
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  (list 'menu-item  "Set Language Environment" setup-language-environment-map
	:help "Multilingual environment suitable for a specific language"))
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(define-key-after mule-menu-keymap [mouse-set-font]
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  '(menu-item "Set Font/Fontset" mouse-set-font
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	       :visible (fboundp 'generate-fontset-menu)
	       :help "Select a font from list of known fonts/fontsets"))
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(define-key-after mule-menu-keymap [separator-mule]
  '("--")
  t)
(define-key-after mule-menu-keymap [toggle-input-method]
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  '(menu-item "Toggle Input Method" toggle-input-method)
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  t)
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(define-key-after mule-menu-keymap [set-input-method]
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  '(menu-item "Select Input Method..." set-input-method)
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  t)
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(define-key-after mule-menu-keymap [describe-input-method]
  '(menu-item "Describe Input Method"  describe-input-method))
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(define-key-after mule-menu-keymap [separator-input-method]
  '("--")
  t)
(define-key-after mule-menu-keymap [set-various-coding-system]
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  (list 'menu-item "Set Coding Systems" set-coding-system-map
	:enable 'enable-multibyte-characters))
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(define-key-after mule-menu-keymap [view-hello-file]
  '(menu-item "Show Multi-lingual Text" view-hello-file
	      :enable (file-readable-p
		       (expand-file-name "HELLO" data-directory))
	      :help "Display file which says HELLO in many languages")
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  t)
(define-key-after mule-menu-keymap [separator-coding-system]
  '("--")
  t)
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(define-key-after mule-menu-keymap [describe-language-environment]
  (list 'menu-item "Describe Language Environment"
	describe-language-environment-map
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	:help "Show multilingual settings for a specific language")
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  t)
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(define-key-after mule-menu-keymap [describe-input-method]
  '(menu-item "Describe Input Method..." describe-input-method
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	      :help "Keyboard layout for a specific input method")
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  t)
(define-key-after mule-menu-keymap [describe-coding-system]
  '(menu-item "Describe Coding System..." describe-coding-system)
  t)
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(define-key-after mule-menu-keymap [list-character-sets]
  '(menu-item "List Character Sets" list-character-sets
	      :help "Show table of available character sets"))
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(define-key-after mule-menu-keymap [mule-diag]
  '(menu-item "Show All of Mule Status" mule-diag
	      :help "Display multilingual environment settings")
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  t)

(define-key-after set-coding-system-map [set-buffer-file-coding-system]
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  '(menu-item "For Saving this Buffer" set-buffer-file-coding-system
	      :help "How to encode this buffer on disk")
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  t)
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(define-key-after set-coding-system-map [universal-coding-system-argument]
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  '(menu-item "For Next Command" universal-coding-system-argument
	      :help "Coding system to be used by next command")
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  t)
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(define-key-after set-coding-system-map [set-terminal-coding-system]
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  '(menu-item "For Terminal" set-terminal-coding-system
	      :enable (null (memq window-system '(x w32 mac)))
	      :help "How to encode terminal output")
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  t)
(define-key-after set-coding-system-map [set-keyboard-coding-system]
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  '(menu-item "For Keyboard" set-keyboard-coding-system
	      :help "How to decode keyboard input")
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  t)
(define-key-after set-coding-system-map [set-buffer-process-coding-system]
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  '(menu-item "For I/O with Subprocess" set-buffer-process-coding-system
	      :visible (fboundp 'start-process)
	      :enable (get-buffer-process (current-buffer))
	      :help "How to en/decode I/O from/to subprocess connected to this buffer")
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  t)
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(define-key-after set-coding-system-map [set-selection-coding-system]
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  '(menu-item "For X Selections/Clipboard" set-selection-coding-system
	      :visible (display-selections-p)
	      :help "How to en/decode data to/from selection/clipboard")
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  t)
(define-key-after set-coding-system-map [set-next-selection-coding-system]
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  '(menu-item "For Next X Selection" set-next-selection-coding-system
	      :visible (display-selections-p)
	      :help "How to en/decode next selection/clipboard operation")
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  t)
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(define-key setup-language-environment-map
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  [Default] '(menu-item "Default" setup-specified-language-environment))
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(define-key describe-language-environment-map
  [Default] '(menu-item "Default" describe-specified-language-support))

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;; This should be a single character key binding because users use it
;; very frequently while editing multilingual text.  Now we can use
;; only two such keys: "\C-\\" and "\C-^", but the latter is not
;; convenient because it requires shifting on most keyboards.  An
;; alternative is "\C-\]" which is now bound to `abort-recursive-edit'
;; but it won't be used that frequently.
(define-key global-map "\C-\\" 'toggle-input-method)

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;;; This is no good because people often type Shift-SPC
;;; meaning to type SPC.  -- rms.
;;; ;; Here's an alternative key binding for X users (Shift-SPACE).
;;; (define-key global-map [?\S- ] 'toggle-input-method)
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;;; Mule related hyperlinks.
(defconst help-xref-mule-regexp-template
  (purecopy (concat "\\(\\<\\("
		    "\\(coding system\\)\\|"
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		    "\\(input method\\)\\|"
		    "\\(character set\\)\\|"
		    "\\(charset\\)"
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		    "\\)\\s-+\\)?"
		    ;; Note starting with word-syntax character:
		    "`\\(\\sw\\(\\sw\\|\\s_\\)+\\)'")))

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(defun coding-system-change-eol-conversion (coding-system eol-type)
  "Return a coding system which differs from CODING-SYSTEM in eol conversion.
The returned coding system converts end-of-line by EOL-TYPE
but text as the same way as CODING-SYSTEM.
EOL-TYPE should be `unix', `dos', `mac', or nil.
If EOL-TYPE is nil, the returned coding system detects
how end-of-line is formatted automatically while decoding.

EOL-TYPE can be specified by an integer 0, 1, or 2.
They means `unix', `dos', and `mac' respectively."
  (if (symbolp eol-type)
      (setq eol-type (cond ((eq eol-type 'unix) 0)
			   ((eq eol-type 'dos) 1)
			   ((eq eol-type 'mac) 2)
			   (t eol-type))))
  (let ((orig-eol-type (coding-system-eol-type coding-system)))
    (if (vectorp orig-eol-type)
	(if (not eol-type)
	    coding-system
	  (aref orig-eol-type eol-type))
      (let ((base (coding-system-base coding-system)))
	(if (not eol-type)
	    base
	  (if (= eol-type orig-eol-type)
	      coding-system
	    (setq orig-eol-type (coding-system-eol-type base))
	    (if (vectorp orig-eol-type)
		(aref orig-eol-type eol-type))))))))

(defun coding-system-change-text-conversion (coding-system coding)
  "Return a coding system which differs from CODING-SYSTEM in text conversion.
The returned coding system converts text by CODING
but end-of-line as the same way as CODING-SYSTEM.
If CODING is nil, the returned coding system detects
how text is formatted automatically while decoding."
  (if (not coding)
      (coding-system-base coding-system)
    (let ((eol-type (coding-system-eol-type coding-system)))
      (coding-system-change-eol-conversion
       coding
       (if (numberp eol-type) (aref [unix dos mac] eol-type))))))

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(defun toggle-enable-multibyte-characters (&optional arg)
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  "Change whether this buffer uses multibyte characters.
With arg, use multibyte characters if the arg is positive.

Note that this command does not convert the byte contents of
the buffer; it only changes the way those bytes are interpreted.
In general, therefore, this command *changes* the sequence of
characters that the current buffer contains.

We suggest you avoid using use this command unless you know what you
are doing.  If you use it by mistake, and the buffer is now displayed
wrong, use this command again to toggle back to the right mode."
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  (interactive "P")
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  (let ((new-flag
	 (if (null arg) (null enable-multibyte-characters)
	   (> (prefix-numeric-value arg) 0))))
    (set-buffer-multibyte new-flag))
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  (force-mode-line-update))

(defun view-hello-file ()
  "Display the HELLO file which list up many languages and characters."
  (interactive)
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  ;; We have to decode the file in any environment.
  (let ((default-enable-multibyte-characters t)
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	(coding-system-for-read 'iso-2022-7bit))
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    (find-file-read-only (expand-file-name "HELLO" data-directory))))
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(defun universal-coding-system-argument ()
  "Execute an I/O command using the specified coding system."
  (interactive)
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  (let* ((default (and buffer-file-coding-system
		       (not (eq (coding-system-type buffer-file-coding-system)
				t))
		       buffer-file-coding-system))
	 (coding-system (read-coding-system
			 (if default
			     (format "Coding system for following command (default, %s): " default)
			   "Coding system for following command: ")
			 default))
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	 (keyseq (read-key-sequence
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		  (format "Command to execute with %s:" coding-system)))
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	 (cmd (key-binding keyseq)))
    (let ((coding-system-for-read coding-system)
	  (coding-system-for-write coding-system))
      (message "")
      (call-interactively cmd))))

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(defun set-default-coding-systems (coding-system)
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  "Set default value of various coding systems to CODING-SYSTEM.
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This sets the following coding systems:
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  o coding system of a newly created buffer
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  o default coding system for subprocess I/O
This also sets the following values:
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  o default value used as file-name-coding-system for converting file names.
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  o default value for the command `set-terminal-coding-system' (not on MSDOS)
  o default value for the command `set-keyboard-coding-system'."
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  (check-coding-system coding-system)
  (setq-default buffer-file-coding-system coding-system)
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  (if default-enable-multibyte-characters
      (setq default-file-name-coding-system coding-system))
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  ;; If coding-system is nil, honor that on MS-DOS as well, so
  ;; that they could reset the terminal coding system.
  (unless (and (eq window-system 'pc) coding-system)
    (setq default-terminal-coding-system coding-system))
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  (setq default-keyboard-coding-system coding-system)
  (setq default-process-coding-system (cons coding-system coding-system)))

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(defalias 'update-iso-coding-systems 'update-coding-systems-internal)
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(make-obsolete 'update-iso-coding-systems 'update-coding-systems-internal "20.3")
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(defun prefer-coding-system (coding-system)
  "Add CODING-SYSTEM at the front of the priority list for automatic detection.
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This also sets the following coding systems:
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  o coding system of a newly created buffer
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  o default coding system for subprocess I/O
This also sets the following values:
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  o default value used as file-name-coding-system for converting file names.
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  o default value for the command `set-terminal-coding-system' (not on MSDOS)
  o default value for the command `set-keyboard-coding-system'

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If CODING-SYSTEM specifies a certain type of EOL conversion, the coding
systems set by this function will use that type of EOL conversion.

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This command does not change the default value of terminal coding system
for MS-DOS terminal, because DOS terminals only support a single coding
system, and Emacs automatically sets the default to that coding system at
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startup.

Such a coding system that requires automatic detection of text
encoding (e.g. undecided, unix) can't be preferred."
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  (interactive "zPrefer coding system: ")
  (if (not (and coding-system (coding-system-p coding-system)))
      (error "Invalid coding system `%s'" coding-system))
  (let ((coding-category (coding-system-category coding-system))
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	(base (coding-system-base coding-system))
	(eol-type (coding-system-eol-type coding-system)))
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    (if (not coding-category)
	;; CODING-SYSTEM is no-conversion or undecided.
	(error "Can't prefer the coding system `%s'" coding-system))
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    (set coding-category (or base coding-system))
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    (update-coding-systems-internal)
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    (or (eq coding-category (car coding-category-list))
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	;; We must change the order.
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	(set-coding-priority (list coding-category)))
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    (if (and base (interactive-p))
	(message "Highest priority is set to %s (base of %s)"
		 base coding-system))
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    ;; If they asked for specific EOL conversion, honor that.
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    (if (memq eol-type '(0 1 2))
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	(setq coding-system
	      (coding-system-change-eol-conversion base eol-type))
      (setq coding-system base))
    (set-default-coding-systems coding-system)))
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(defvar sort-coding-systems-predicate nil
  "If non-nil, a predicate function to sort coding systems.

It is called with two coding systems, and should return t if the first
one is \"less\" than the second.

The function `sort-coding-systems' use it.")

(defun sort-coding-systems (codings)
  "Sort coding system list CODINGS by a priority of each coding system.

If a coding system is most preferred, it has the highest priority.
Otherwise, a coding system corresponds to some MIME charset has higher
priorities.  Among them, a coding system included in `coding-system'
key of the current language environment has higher priorities.  See
also the documentation of `language-info-alist'.

If the variable `sort-coding-systems-predicate' (which see) is
non-nil, it is used to sort CODINGS in the different way than above."
  (if sort-coding-systems-predicate
      (sort codings sort-coding-systems-predicate)
    (let* ((most-preferred (symbol-value (car coding-category-list)))
	   (lang-preferred (get-language-info current-language-environment
					      'coding-system))
	   (func (function
		  (lambda (x)
		    (let ((base (coding-system-base x)))
		      (+ (if (eq base most-preferred) 64 0)
			 (let ((mime (coding-system-get base 'mime-charset)))
			   (if mime
			       (if (string-match "^x-" (symbol-name mime))
				   16 32)
			     0))
			 (if (memq base lang-preferred) 8 0)
			 (if (string-match "-with-esc$" (symbol-name base))
			     0 4)
			 (if (eq (coding-system-type base) 2)
			     ;; For ISO based coding systems, prefer
			     ;; one that doesn't use escape sequences.
			     (let ((flags (coding-system-flags base)))
			       (if (or (consp (aref flags 0))
				       (consp (aref flags 1))
				       (consp (aref flags 2))
				       (consp (aref flags 3)))
				   (if (or (aref flags 8) (aref flags 9))
				       0
				     1)
				 2))
			   1)))))))
      (sort codings (function (lambda (x y)
				(> (funcall func x) (funcall func y))))))))
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(defun find-coding-systems-region (from to)
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  "Return a list of proper coding systems to encode a text between FROM and TO.
All coding systems in the list can safely encode any multibyte characters
in the text.

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If the text contains no multibyte characters, return a list of a single
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element `undecided'."
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  (let ((codings (find-coding-systems-region-internal from to)))
    (if (eq codings t)
	;; The text contains only ASCII characters.  Any coding
	;; systems are safe.
	'(undecided)
      ;; We need copy-sequence because sorting will alter the argument.
      (sort-coding-systems (copy-sequence codings)))))
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(defun find-coding-systems-string (string)
  "Return a list of proper coding systems to encode STRING.
All coding systems in the list can safely encode any multibyte characters
in STRING.

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If STRING contains no multibyte characters, return a list of a single
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element `undecided'."
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  (find-coding-systems-region string nil))
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(defun find-coding-systems-for-charsets (charsets)
  "Return a list of proper coding systems to encode characters of CHARSETS.
CHARSETS is a list of character sets."
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  (cond ((or (null charsets)
	     (and (= (length charsets) 1)
		  (eq 'ascii (car charsets))))
	 '(undecided))
	((or (memq 'eight-bit-control charsets)
	     (memq 'eight-bit-graphic charsets))
	 '(raw-text emacs-mule))
	(t
	 (let ((codings t)
	       charset l ll)
	   (while (and codings charsets)
	     (setq charset (car charsets) charsets (cdr charsets))
	     (unless (eq charset 'ascii)
	       (setq l (aref char-coding-system-table (make-char charset)))
	       (if (eq codings t)
		   (setq codings l)
		 (let ((ll nil))
		   (while codings
		     (if (memq (car codings) l)
			 (setq ll (cons (car codings) ll)))
		     (setq codings (cdr codings)))
		   (setq codings ll)))))
	   (append codings
		   (char-table-extra-slot char-coding-system-table 0))))))
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(defun find-multibyte-characters (from to &optional maxcount excludes)
  "Find multibyte characters in the region specified by FROM and TO.
If FROM is a string, find multibyte characters in the string.
The return value is an alist of the following format:
  ((CHARSET COUNT CHAR ...) ...)
where
  CHARSET is a character set,
  COUNT is a number of characters,
  CHARs are found characters of the character set.
Optional 3rd arg MAXCOUNT limits how many CHARs are put in the above list.
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Optional 4th arg EXCLUDE is a list of character sets to be ignored.

For invalid characters, CHARs are actually strings."
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  (let ((chars nil)
	charset char)
    (if (stringp from)
	(let ((idx 0))
	  (while (setq idx (string-match "[^\000-\177]" from idx))
	    (setq char (aref from idx)
		  charset (char-charset char))
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	    (if (eq charset 'unknown)
		(setq char (match-string 0)))
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	    (if (or (memq charset '(unknown
				    eight-bit-control eight-bit-graphic))
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		    (not (or (eq excludes t) (memq charset excludes))))
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		(let ((slot (assq charset chars)))
		  (if slot
		      (if (not (memq char (nthcdr 2 slot)))
			  (let ((count (nth 1 slot)))
			    (setcar (cdr slot) (1+ count))
			    (if (or (not maxcount) (< count maxcount))
				(nconc slot (list char)))))
		    (setq chars (cons (list charset 1 char) chars)))))
	    (setq idx (1+ idx))))
      (save-excursion
	(goto-char from)
	(while (re-search-forward "[^\000-\177]" to t)
	  (setq char (preceding-char)
		charset (char-charset char))
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	  (if (eq charset 'unknown)
	      (setq char (match-string 0)))
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	  (if (or (memq charset '(unknown eight-bit-control eight-bit-graphic))
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		  (not (or (eq excludes t) (memq charset excludes))))
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	      (let ((slot (assq charset chars)))
		(if slot
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		    (if (not (member char (nthcdr 2 slot)))
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			(let ((count (nth 1 slot)))
			  (setcar (cdr slot) (1+ count))
			  (if (or (not maxcount) (< count maxcount))
			      (nconc slot (list char)))))
		  (setq chars (cons (list charset 1 char) chars))))))))
    (nreverse chars)))

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(defvar last-coding-system-specified nil
  "Most recent coding system explicitly specified by the user when asked.
This variable is set whenever Emacs asks the user which coding system
to use in order to write a file.  If you set it to nil explicitly,
then call `write-region', then afterward this variable will be non-nil
only if the user was explicitly asked and specified a coding system.")

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(defvar select-safe-coding-system-accept-default-p nil
  "If non-nil, a function to control the behaviour of coding system selection.
The meaning is the same as the argument ACCEPT-DEFAULT-P of the
function `select-safe-coding-system' (which see).  This variable
overrides that argument.")

(defun select-safe-coding-system (from to &optional default-coding-system
				       accept-default-p)
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  "Ask a user to select a safe coding system from candidates.
The candidates of coding systems which can safely encode a text
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between FROM and TO are shown in a popup window.  Among them, the most
proper one is suggested as the default.

The list of `buffer-file-coding-system' of the current buffer and the
most preferred coding system (if it corresponds to a MIME charset) is
treated as the default coding system list.  Among them, the first one
that safely encodes the text is silently selected and returned without
any user interaction.  See also the command `prefer-coding-system'.
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Optional 3rd arg DEFAULT-CODING-SYSTEM specifies a coding system or a
list of coding systems to be prepended to the default coding system
list.
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Optional 4th arg ACCEPT-DEFAULT-P, if non-nil, is a function to
determine the acceptability of the silently selected coding system.
It is called with that coding system, and should return nil if it
should not be silently selected and thus user interaction is required.

The variable `select-safe-coding-system-accept-default-p', if
non-nil, overrides ACCEPT-DEFAULT-P.
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Kludgy feature: if FROM is a string, the string is the target text,
and TO is ignored."
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  (if (and default-coding-system
	   (not (listp default-coding-system)))
      (setq default-coding-system (list default-coding-system)))

  ;; Change elements of the list to (coding . base-coding).
  (setq default-coding-system
	(mapcar (function (lambda (x) (cons x (coding-system-base x))))
		default-coding-system))

  ;; If buffer-file-coding-system is not nil nor undecided, append it
  ;; to the defaults.
  (if buffer-file-coding-system
      (let ((base (coding-system-base buffer-file-coding-system)))
	(or (eq base 'undecided)
	    (assq buffer-file-coding-system default-coding-system)
	    (rassq base default-coding-system)
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	    (setq default-coding-system
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		  (append default-coding-system
			  (list (cons buffer-file-coding-system base)))))))

  ;; If the most preferred coding system has the property mime-charset,
  ;; append it to the defaults.
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  (let ((tail coding-category-list)
	preferred base)
    (while (and tail
		(not (setq preferred (symbol-name (car tail)))))
      (setq tail (cdr tail)))
    (and (coding-system-p preferred)
	 (setq base (coding-system-base preferred))
	 (coding-system-get preferred 'mime-charset)
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	 (not (assq preferred default-coding-system))
	 (not (rassq base default-coding-system))
	 (setq default-coding-system
	       (append default-coding-system (list (cons preferred base))))))

  (if select-safe-coding-system-accept-default-p
      (setq accept-default-p select-safe-coding-system-accept-default-p))

  (let ((codings (find-coding-systems-region from to))
	(coding-system nil)
	(l default-coding-system))
    (if (eq (car codings) 'undecided)
	;; Any coding system is ok.
	(setq coding-system t)
      ;; Try the defaults.
      (while (and l (not coding-system))
	(if (memq (cdr (car l)) codings)
	    (setq coding-system (car (car l)))
	  (setq l (cdr l))))
      (if (and coding-system accept-default-p)
	  (or (funcall accept-default-p coding-system)
	      (setq coding-system (list coding-system)))))

    ;; If all the defaults failed, ask a user.
    (when (or (not coding-system) (consp coding-system))
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      ;; At first, change each coding system to the corresponding
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      ;; mime-charset name if it is also a coding system.  Such a name
      ;; is more friendly to users.
      (let ((l codings)
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	    mime-charset)
	(while l
	  (setq mime-charset (coding-system-get (car l) 'mime-charset))
	  (if (and mime-charset (coding-system-p mime-charset))
	      (setcar l mime-charset))
	  (setq l (cdr l))))

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      ;; Then ask users to select one form CODINGS.
      (unwind-protect
	  (save-window-excursion
	    (with-output-to-temp-buffer "*Warning*"
	      (save-excursion
		(set-buffer standard-output)
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		(if (not default-coding-system)
		    (insert "No default coding systems to try.")
		  (insert "These default coding systems were tried")
		  (if (stringp from)
		      (insert " to encode \""
			      (if (> (length from) 10)
				  (substring from 0 10)
				from)
			      "...\""))
		  (insert ":\n")
		  (let ((pos (point))
			(fill-prefix "  "))
		    (mapcar (function (lambda (x)
					(princ "  ") (princ (car x))))
			    default-coding-system)
		    (insert "\n")
		    (fill-region-as-paragraph pos (point)))
		  (insert
		   (if (consp coding-system)
		       (concat (format "%s safely encodes the target text,\n"
				       (car coding-system))
			       "but it is not recommended for encoding text in this context,\n"
			       "e.g., for sending an email message.\n")
		     "However, none of them safely encodes the target text.\n")))
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		(insert (if (consp coding-system)
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			    "\nSelect the above, or "
			  "\nSelect ")
			"one of the following safe coding systems:\n")
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		(let ((pos (point))
		      (fill-prefix "  "))
		  (mapcar (function (lambda (x) (princ "  ") (princ x)))
			  codings)
		  (insert "\n")
		  (fill-region-as-paragraph pos (point)))))

	    ;; Read a coding system.
	    (if (consp coding-system)
		(setq codings (cons (car coding-system) codings)))
	    (let* ((safe-names (mapcar (lambda (x) (list (symbol-name x)))
				       codings))
		   (name (completing-read
			  (format "Select coding system (default %s): "
				  (car codings))
			  safe-names nil t nil nil
			  (car (car safe-names)))))
	      (setq last-coding-system-specified (intern name)
		    coding-system last-coding-system-specified)))
	(kill-buffer "*Warning*")))

    (if (vectorp (coding-system-eol-type coding-system))
	(let ((eol (coding-system-eol-type buffer-file-coding-system)))
	  (if (numberp eol)
	      (setq coding-system
		    (coding-system-change-eol-conversion coding-system eol)))))

    (if (eq coding-system t)
	(setq coding-system buffer-file-coding-system))
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    coding-system))
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(setq select-safe-coding-system-function 'select-safe-coding-system)

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(defun select-message-coding-system ()
  "Return a coding system to encode the outgoing message of the current buffer.
It at first tries the first coding system found in these variables
in this order:
  (1) local value of `buffer-file-coding-system'
  (2) value of `sendmail-coding-system'
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  (3) value of `default-sendmail-coding-system'
  (4) value of `default-buffer-file-coding-system'
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If the found coding system can't encode the current buffer,
or none of them are bound to a coding system,
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it asks the user to select a proper coding system."
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  (let ((coding (or (and (local-variable-p 'buffer-file-coding-system)
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			  buffer-file-coding-system)
		     sendmail-coding-system
		     default-sendmail-coding-system
		     default-buffer-file-coding-system)))
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    (if (eq coding 'no-conversion)
	;; We should never use no-conversion for outgoing mails.
	(setq coding nil))
    (if (fboundp select-safe-coding-system-function)
	(funcall select-safe-coding-system-function
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		 (point-min) (point-max) coding
		 (function (lambda (x) (coding-system-get x 'mime-charset))))
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      coding)))
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;;; Language support stuff.
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(defvar language-info-alist nil
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  "Alist of language environment definitions.
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Each element looks like:
	(LANGUAGE-NAME . ((KEY . INFO) ...))
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where LANGUAGE-NAME is a string, the name of the language environment,
KEY is a symbol denoting the kind of information, and
INFO is the data associated with KEY.
Meaningful values for KEY include

  documentation      value is documentation of what this language environment
			is meant for, and how to use it.
  charset	     value is a list of the character sets used by this
			language environment.
  sample-text	     value is one line of text,
			written using those character sets,
			appropriate for this language environment.
  setup-function     value is a function to call to switch to this
			language environment.
  exit-function      value is a function to call to leave this
		        language environment.
  coding-system      value is a list of coding systems that are good
			for saving text written in this language environment.
			This list serves as suggestions to the user;
			in effect, as a kind of documentation.
  coding-priority    value is a list of coding systems for this language
			environment, in order of decreasing priority.
			This is used to set up the coding system priority
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			list when you switch to this language environment.
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  nonascii-translation
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		     value is a translation table to be set in the
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			variable `nonascii-translation-table' in this
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			language environment, or a character set from
			which `nonascii-insert-offset' is calculated.
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  input-method       value is a default input method for this language
			environment.
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  features           value is a list of features requested in this
			language environment.
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The following keys take effect only when multibyte characters are
globally disabled, i.e. the value of `default-enable-multibyte-characters'
is nil.

  unibyte-syntax     value is a library name to load to set
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			unibyte 8-bit character syntaxes for this
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			language environment.

  unibyte-display    value is a coding system to encode characters
			for the terminal.  Characters in the range
			of 160 to 255 display not as octal escapes,
			but as non-ASCII characters in this language
			environment.")
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(defun get-language-info (lang-env key)
  "Return information listed under KEY for language environment LANG-ENV.
KEY is a symbol denoting the kind of information.
For a list of useful values for KEY and their meanings,
see `language-info-alist'."
  (if (symbolp lang-env)
      (setq lang-env (symbol-name lang-env)))
  (let ((lang-slot (assoc-ignore-case lang-env language-info-alist)))
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    (if lang-slot
	(cdr (assq key (cdr lang-slot))))))

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(defun set-language-info (lang-env key info)
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  "Modify part of the definition of language environment LANG-ENV.
Specifically, this stores the information INFO under KEY
in the definition of this language environment.
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KEY is a symbol denoting the kind of information.
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INFO is the value for that information.
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For a list of useful values for KEY and their meanings,
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see `language-info-alist'."
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  (if (symbolp lang-env)
      (setq lang-env (symbol-name lang-env)))
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  (let (lang-slot key-slot)
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    (setq lang-slot (assoc lang-env language-info-alist))
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    (if (null lang-slot)		; If no slot for the language, add it.
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	(setq lang-slot (list lang-env)
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	      language-info-alist (cons lang-slot language-info-alist)))
    (setq key-slot (assq key lang-slot))
    (if (null key-slot)			; If no slot for the key, add it.
	(progn
	  (setq key-slot (list key))
	  (setcdr lang-slot (cons key-slot (cdr lang-slot)))))
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    (setcdr key-slot (purecopy info))))
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(defun set-language-info-alist (lang-env alist &optional parents)
  "Store ALIST as the definition of language environment LANG-ENV.
ALIST is an alist of KEY and INFO values.  See the documentation of
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`language-info-alist' for the meanings of KEY and INFO.
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Optional arg PARENTS is a list of parent menu names; it specifies
where to put this language environment in the 
Describe Language Environment and Set Language Environment menus.
For example, (\"European\") means to put this language environment
in the European submenu in each of those two menus."
  (if (symbolp lang-env)
      (setq lang-env (symbol-name lang-env)))
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  (let ((describe-map describe-language-environment-map)
	(setup-map setup-language-environment-map))
    (if parents
	(let ((l parents)
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	      map parent-symbol parent prompt)
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	  (while l
	    (if (symbolp (setq parent-symbol (car l)))
		(setq parent (symbol-name parent))
	      (setq parent parent-symbol parent-symbol (intern parent)))
	    (setq map (lookup-key describe-map (vector parent-symbol)))
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	    ;; This prompt string is for define-prefix-command, so
	    ;; that the map it creates will be suitable for a menu.
	    (or map (setq prompt (format "%s Environment" parent)))
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	    (if (not map)
		(progn
		  (setq map (intern (format "describe-%s-environment-map"
					    (downcase parent))))
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		  (define-prefix-command map nil prompt)
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		  (define-key-after describe-map (vector parent-symbol)
		    (cons parent map) t)))
	    (setq describe-map (symbol-value map))
	    (setq map (lookup-key setup-map (vector parent-symbol)))
	    (if (not map)
		(progn
		  (setq map (intern (format "setup-%s-environment-map"
					    (downcase parent))))
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		  (define-prefix-command map nil prompt)
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		  (define-key-after setup-map (vector parent-symbol)
		    (cons parent map) t)))
	    (setq setup-map (symbol-value map))
	    (setq l (cdr l)))))
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    ;; Set up menu items for this language env.
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    (let ((doc (assq 'documentation alist)))
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      (when doc
	(define-key-after describe-map (vector (intern lang-env))
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	  (cons lang-env 'describe-specified-language-support) t)))
    (define-key-after setup-map (vector (intern lang-env))
      (cons lang-env 'setup-specified-language-environment) t)
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    (while alist
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      (set-language-info lang-env (car (car alist)) (cdr (car alist)))
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      (setq alist (cdr alist)))))
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(defun read-language-name (key prompt &optional default)
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  "Read a language environment name which has information for KEY.
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If KEY is nil, read any language environment.
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Prompt with PROMPT.  DEFAULT is the default choice of language environment.
This returns a language environment name as a string."
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  (let* ((completion-ignore-case t)
	 (name (completing-read prompt
				language-info-alist
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				(and key
				     (function (lambda (elm) (assq key elm))))
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				t nil nil default)))
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    (if (and (> (length name) 0)
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	     (or (not key)
		 (get-language-info name key)))
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	name)))
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854 855

;;; Multilingual input methods.
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(defgroup leim nil 
  "LEIM: Libraries of Emacs Input Methods."
  :group 'mule)
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(defconst leim-list-file-name "leim-list.el"
  "Name of LEIM list file.
This file contains a list of libraries of Emacs input methods (LEIM)
in the format of Lisp expression for registering each input method.
Emacs loads this file at startup time.")

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(defvar leim-list-header (format
";;; %s -- list of LEIM (Library of Emacs Input Method)
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;;
;; This file contains a list of LEIM (Library of Emacs Input Method)
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;; in the same directory as this file.  Loading this file registers
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;; the whole input methods in Emacs.
;;
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;; Each entry has the form:
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;;   (register-input-method
;;    INPUT-METHOD LANGUAGE-NAME ACTIVATE-FUNC
;;    TITLE DESCRIPTION
;;    ARG ...)
;; See the function `register-input-method' for the meanings of arguments.
;;
;; If this directory is included in load-path, Emacs automatically
;; loads this file at startup time.

"
				 leim-list-file-name)
  "Header to be inserted in LEIM list file.")

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(defvar leim-list-entry-regexp "^(register-input-method"
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  "Regexp matching head of each entry in LEIM list file.
See also the variable `leim-list-header'")

(defvar update-leim-list-functions
  '(quail-update-leim-list-file)
  "List of functions to call to update LEIM list file.
Each function is called with one arg, LEIM directory name.")

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(defun update-leim-list-file (&rest dirs)
  "Update LEIM list file in directories DIRS."
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  (let ((functions update-leim-list-functions))
    (while functions
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      (apply (car functions) dirs)
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      (setq functions (cdr functions)))))

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(defvar current-input-method nil
  "The current input method for multilingual text.
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If nil, that means no input method is activated now.")
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(make-variable-buffer-local 'current-input-method)
(put 'current-input-method 'permanent-local t)

(defvar current-input-method-title nil
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  "Title string of the current input method shown in mode line.")
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(make-variable-buffer-local 'current-input-method-title)
(put 'current-input-method-title 'permanent-local t)

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(defcustom default-input-method nil
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  "*Default input method for multilingual text (a string).
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This is the input method activated automatically by the command
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`toggle-input-method' (\\[toggle-input-method])."
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  :group 'mule
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  :type '(choice (const nil) string)
  :set-after '(current-language-environment))
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(put 'input-method-function 'permanent-local t)

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(defvar input-method-history nil
  "History list for some commands that read input methods.")
(make-variable-buffer-local 'input-method-history)
(put 'input-method-history 'permanent-local t)
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(defvar inactivate-current-input-method-function nil
  "Function to call for inactivating the current input method.
Every input method should set this to an appropriate value when activated.
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This function is called with no argument.

This function should never change the value of `current-input-method'.
It is set to nil by the function `inactivate-input-method'.")
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(make-variable-buffer-local 'inactivate-current-input-method-function)
(put 'inactivate-current-input-method-function 'permanent-local t)

(defvar describe-current-input-method-function nil
  "Function to call for describing the current input method.
This function is called with no argument.")
(make-variable-buffer-local 'describe-current-input-method-function)
(put 'describe-current-input-method-function 'permanent-local t)

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(defvar input-method-alist nil
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  "Alist of input method names vs how to use them.
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Each element has the form:
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   (INPUT-METHOD LANGUAGE-ENV ACTIVATE-FUNC TITLE DESCRIPTION ARGS...)
See the function `register-input-method' for the meanings of the elements.")

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(defun register-input-method (input-method lang-env &rest args)
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  "Register INPUT-METHOD as an input method for language environment ENV.
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INPUT-METHOD and LANG-ENV are symbols or strings.
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The remaining arguments are:
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	ACTIVATE-FUNC, TITLE, DESCRIPTION, and ARGS...
ACTIVATE-FUNC is a function to call to activate this method.
TITLE is a string to show in the mode line when this method is active.
DESCRIPTION is a string describing this method and what it is good for.
The ARGS, if any, are passed as arguments to ACTIVATE-FUNC.
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All told, the arguments to ACTIVATE-FUNC are INPUT-METHOD and the ARGS.

This function is mainly used in the file \"leim-list.el\" which is
created at building time of emacs, registering all quail input methods
contained in the emacs distribution.

In case you want to register a new quail input method by yourself, be
careful to use the same input method title as given in the third
parameter of `quail-define-package' (if the values are different, the
string specified in this function takes precedence).

The commands `describe-input-method' and `list-input-methods' need
this duplicated values to show some information about input methods
without loading the affected quail packages."
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  (if (symbolp lang-env)
      (setq lang-env (symbol-name lang-env)))
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  (if (symbolp input-method)
      (setq input-method (symbol-name input-method)))
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  (let ((info (cons lang-env args))
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	(slot (assoc input-method input-method-alist)))
    (if slot
	(setcdr slot info)
      (setq slot (cons input-method info))
      (setq input-method-alist (cons slot input-method-alist)))))

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(defun read-input-method-name (prompt &optional default inhibit-null)
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  "Read a name of input method from a minibuffer prompting with PROMPT.
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If DEFAULT is non-nil, use that as the default,
  and substitute it into PROMPT at the first `%s'.
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If INHIBIT-NULL is non-nil, null input signals an error.

The return value is a string."
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  (if default
      (setq prompt (format prompt default)))
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  (let* ((completion-ignore-case t)
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	 ;; This binding is necessary because input-method-history is
	 ;; buffer local.
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	 (input-method (completing-read prompt input-method-alist
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					nil t nil 'input-method-history
					default)))
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    (if (and input-method (symbolp input-method))
	(setq input-method (symbol-name input-method)))
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    (if (> (length input-method) 0)
	input-method
      (if inhibit-null
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	  (error "No valid input method is specified")))))
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(defun activate-input-method (input-method)
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  "Switch to input method INPUT-METHOD for the current buffer.
If some other input method is already active, turn it off first.
If INPUT-METHOD is nil, deactivate any current input method."
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  (if (and input-method (symbolp input-method))
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      (setq input-method (symbol-name input-method)))
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  (if (and current-input-method
	   (not (string= current-input-method input-method)))
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      (inactivate-input-method))
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  (unless (or current-input-method (null input-method))
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    (let ((slot (assoc input-method input-method-alist)))
      (if (null slot)
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	  (error "Can't activate input method `%s'" input-method))
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      (let ((func (nth 2 slot)))
	(if (functionp func)
	    (apply (nth 2 slot) input-method (nthcdr 5 slot))
	  (if (and (consp func) (symbolp (car func)) (symbolp (cdr func)))
	      (progn
		(require (cdr func))
		(apply (car func) input-method (nthcdr 5 slot)))
	    (error "Can't activate input method `%s'" input-method))))
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      (setq current-input-method input-method)
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      (setq current-input-method-title (nth 3 slot))
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      (unwind-protect
	  (run-hooks 'input-method-activate-hook)
	(force-mode-line-update)))))
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(defun inactivate-input-method ()
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  "Turn off the current input method."
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