[bpt/emacs.git] / lisp / international / mule-cmds.el

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

;; Copyright (C) 1995 Electrotechnical Laboratory, JAPAN.
;; Licensed to the Free Software Foundation.

;; 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
;; 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.

;;; Code:

;;; MULE related key bindings and menus.

(defvar mule-keymap (make-sparse-keymap)
  "Keymap for MULE (Multilingual environment) specific commands.")

;; Keep "C-x C-m ..." for mule specific commands.
(define-key ctl-x-map "\C-m" mule-keymap)

(define-key mule-keymap "f" 'set-buffer-file-coding-system)
(define-key mule-keymap "t" 'set-terminal-coding-system)
(define-key mule-keymap "k" 'set-keyboard-coding-system)
(define-key mule-keymap "p" 'set-buffer-process-coding-system)
(define-key mule-keymap "\C-\\" 'set-input-method)
(define-key mule-keymap "c" 'universal-coding-system-argument)
(define-key mule-keymap "l" 'set-language-environment)

(define-key help-map "\C-L" 'describe-language-environment)
(define-key help-map "L" 'describe-language-environment)
(define-key help-map "\C-\\" 'describe-input-method)
(define-key help-map "I" 'describe-input-method)
(define-key help-map "C" 'describe-coding-system)
(define-key help-map "h" 'view-hello-file)

(defvar mule-menu-keymap (make-sparse-keymap "Mule")
  "Keymap for MULE (Multilingual environment) menu specific commands.")

(define-key global-map [menu-bar mule]
  `(menu-item "Mule" ,mule-menu-keymap
	      :visible default-enable-multibyte-characters))

(setq menu-bar-final-items (cons 'mule menu-bar-final-items))

(defvar describe-language-environment-map nil)
(define-prefix-command 'describe-language-environment-map)

(defvar setup-language-environment-map nil)
(define-prefix-command 'setup-language-environment-map)

(defvar set-coding-system-map nil)
(define-prefix-command 'set-coding-system-map)

(define-key-after mule-menu-keymap [describe-language-environment]
  '("Describe Language Environment" . describe-language-environment-map)
  t)
(define-key-after mule-menu-keymap [set-language-environment]
  '("Set Language Environment" . setup-language-environment-map)
  t)
(define-key-after mule-menu-keymap [mouse-set-font]
  '("Set Font/Fontset" . mouse-set-font)
  t)
(define-key-after mule-menu-keymap [separator-mule]
  '("--")
  t)
(define-key-after mule-menu-keymap [toggle-input-method]
  '("Toggle Input Method" . toggle-input-method)
  t)
(define-key-after mule-menu-keymap [set-input-method]
  '("Select Input Method" . set-input-method)
  t)
(define-key-after mule-menu-keymap [describe-input-method]
  '("Describe Input Method" . describe-input-method)
  t)
(define-key-after mule-menu-keymap [separator-input-method]
  '("--")
  t)
(define-key-after mule-menu-keymap [describe-coding-system]
  '("Describe Coding Systems" . describe-coding-system)
  t)
(define-key-after mule-menu-keymap [set-various-coding-system]
  '("Set Coding System" . set-coding-system-map)
  t)
(define-key-after mule-menu-keymap [separator-coding-system]
  '("--")
  t)
(define-key-after mule-menu-keymap [mule-diag]
  '("Show All of MULE Status" . mule-diag)
  t)
(define-key-after mule-menu-keymap [view-hello-file]
  '("Show Script Examples" . view-hello-file)
  t)

(define-key-after set-coding-system-map [set-buffer-file-coding-system]
  '("Buffer File" . set-buffer-file-coding-system)
  t)
(define-key-after set-coding-system-map [universal-coding-system-argument]
  '("Next Command" . universal-coding-system-argument)
  t)
(define-key-after set-coding-system-map [set-terminal-coding-system]
  '("Terminal" . set-terminal-coding-system)
  t)
(define-key-after set-coding-system-map [set-keyboard-coding-system]
  '("Keyboard" . set-keyboard-coding-system)
  t)
(define-key-after set-coding-system-map [set-buffer-process-coding-system]
  '("Buffer Process" . set-buffer-process-coding-system)
  t)

(define-key setup-language-environment-map
  [Default] '("Default" . setup-specified-language-environment))

;; These are meaningless when running under X.
(put 'set-terminal-coding-system 'menu-enable
     '(not (eq window-system 'x)))
(put 'set-keyboard-coding-system 'menu-enable
     '(not (eq window-system 'x)))
;; This is meaningless when the current buffer has no process.
(put 'set-buffer-process-coding-system 'menu-enable
     '(get-buffer-process (current-buffer)))

;; 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)

;;; 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)

(defun toggle-enable-multibyte-characters (&optional arg)
  "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."
  (interactive "P")
  (let ((new-flag
	 (if (null arg) (null enable-multibyte-characters)
	   (> (prefix-numeric-value arg) 0))))
    (set-buffer-multibyte new-flag))
  (force-mode-line-update))

(defun view-hello-file ()
  "Display the HELLO file which list up many languages and characters."
  (interactive)
  ;; We have to decode the file in any environment.
  (let ((default-enable-multibyte-characters t)
	(coding-system-for-read 'iso-2022-7bit))
    (find-file-read-only (expand-file-name "HELLO" data-directory))))

(defun universal-coding-system-argument ()
  "Execute an I/O command using the specified coding system."
  (interactive)
  (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))
	 (keyseq (read-key-sequence
		  (format "Command to execute with %s:" coding-system)))
	 (cmd (key-binding keyseq)))
    (let ((coding-system-for-read coding-system)
	  (coding-system-for-write coding-system))
      (message "")
      (call-interactively cmd))))

(defun set-default-coding-systems (coding-system)
  "Set default value of various coding systems to CODING-SYSTEM.
This sets the following coding systems:
  o coding system of a newly created buffer
  o default coding system for subprocess I/O
This also sets the following values:
  o default value used as file-name-coding-system for converting file names.
  o default value for the command `set-terminal-coding-system'
  o default value for the command `set-keyboard-coding-system'"
  (check-coding-system coding-system)
  (setq-default buffer-file-coding-system coding-system)
  (setq default-file-name-coding-system coding-system)
  (setq default-terminal-coding-system coding-system)
  (setq default-keyboard-coding-system coding-system)
  (setq default-process-coding-system (cons coding-system coding-system)))

(defun prefer-coding-system (coding-system)
  "Add CODING-SYSTEM at the front of the priority list for automatic detection.
This also sets the following coding systems:
  o coding system of a newly created buffer
  o default coding system for subprocess I/O
This also sets the following values:
  o default value used as file-name-coding-system for converting file names.
  o default value for the command `set-terminal-coding-system'
  o default value for the command `set-keyboard-coding-system'"
  (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))
	(base (coding-system-base coding-system)))
    (if (not coding-category)
	;; CODING-SYSTEM is no-conversion or undecided.
	(error "Can't prefer the coding system `%s'" coding-system))
    (set coding-category (or base coding-system))
    (update-iso-coding-systems)
    (if (not (eq coding-category (car coding-category-list)))
	;; We must change the order.
	(setq coding-category-list
	      (cons coding-category
		    (delq coding-category coding-category-list))))
    (if (and base (interactive-p))
	(message "Highest priority is set to %s (base of %s)"
		 base coding-system))
    (set-default-coding-systems (or base coding-system))))

(defun find-coding-systems-region-subset-p (list1 list2)
  "Return non-nil if all elements in LIST1 are included in LIST2.
Comparison done with EQ."
  (catch 'tag
    (while list1
      (or (memq (car list1) list2)
	  (throw 'tag nil))
      (setq list1 (cdr list1)))
    t))

(defun find-coding-systems-region (from to)
  "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.

If the text contains no multibyte charcters, return a list of a single
element `undecided'."
  (find-coding-systems-for-charsets (find-charset-region from to)))

(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.

If STRING contains no multibyte charcters, return a list of a single
element `undecided'."
  (find-coding-systems-for-charsets (find-charset-string string)))

(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."
  (if (or (null charsets)
	  (and (= (length charsets) 1)
	       (eq 'ascii (car charsets))))
      '(undecided)
    (let ((l coding-system-list)
	  (charset-prefered-codings
	   (mapcar (function
		    (lambda (x)
		      (get-charset-property x 'prefered-coding-system)))
		   charsets))
	  (priorities (mapcar (function (lambda (x) (symbol-value x)))
			      coding-category-list))
	  codings coding safe)
      (while l
	(setq coding (car l) l (cdr l))
	(if (and (eq coding (coding-system-base coding))
		 (setq safe (coding-system-get coding 'safe-charsets))
		 (or (eq safe t)
		     (find-coding-systems-region-subset-p charsets safe)))
	    ;; We put the higher priority to coding systems included
	    ;; in CHARSET-PREFERED-CODINGS, and within them, put the
	    ;; higher priority to coding systems which support smaller
	    ;; number of charsets.
	    (let ((priority
		   (+ (if (coding-system-get coding 'mime-charset) 4096 0)
		      (lsh (length (memq coding priorities)) 7)
		      (if (memq coding charset-prefered-codings) 64 0)
		      (if (> (coding-system-type coding) 0) 32 0)
		      (if (consp safe) (- 32 (length safe)) 0))))
	      (setq codings (cons (cons priority coding) codings)))))
      (mapcar 'cdr
	      (sort codings (function (lambda (x y) (> (car x) (car y))))))
      )))

(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.")

(defun select-safe-coding-system (from to &optional default-coding-system)
  "Ask a user to select a safe coding system from candidates.
The candidates of coding systems which can safely encode a text
between FROM and TO are shown in a popup window.

Optional arg DEFAULT-CODING-SYSTEM specifies a coding system to be
checked at first.  If omitted, buffer-file-coding-system of the
current buffer is used.

If the text can be encoded safely by DEFAULT-CODING-SYSTEM, it is
returned without any user interaction.

Kludgy feature: if FROM is a string, the string is the target text,
and TO is ignored."
  (or default-coding-system
      (setq default-coding-system buffer-file-coding-system))
  (let ((safe-coding-systems (if (stringp from)
				 (find-coding-systems-string from)
			       (find-coding-systems-region from to))))
    (if (or (eq (car safe-coding-systems) 'undecided)
	    (and default-coding-system
		 (memq (coding-system-base default-coding-system)
		       safe-coding-systems)))
	default-coding-system

      ;; At first, change each coding system to the corresponding
      ;; mime-charset name if it is also a coding system.
      (let ((l safe-coding-systems)
	    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))))

      ;; Then, ask a user to select a proper coding system.  
      (save-window-excursion
	;; At first, show a helpful message.
	(with-output-to-temp-buffer "*Warning*"
	  (save-excursion
	    (set-buffer standard-output)
	    (insert (format "\
The target text contains a multibyte character which can't be
encoded safely by the coding system %s.

Please select one from the following safe coding systems:\n"
			    default-coding-system))
	    (let ((pos (point))
		  (fill-prefix "  "))
	      (mapcar (function (lambda (x) (princ "  ") (princ x)))
		      safe-coding-systems)
	      (fill-region-as-paragraph pos (point)))))

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

(setq select-safe-coding-system-function 'select-safe-coding-system)

\f
;;; Language support staffs.

(defvar language-info-alist nil
  "Alist of language environment definitions.
Each element looks like:
	(LANGUAGE-NAME . ((KEY . INFO) ...))
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
			list when you switch to this language environment.")

(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)))
    (if lang-slot
	(cdr (assq key (cdr lang-slot))))))

(defun set-language-info (lang-env key info)
  "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.
KEY is a symbol denoting the kind of information.
INFO is the value for that 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 key-slot)
    (setq lang-slot (assoc lang-env language-info-alist))
    (if (null lang-slot)		; If no slot for the language, add it.
	(setq lang-slot (list lang-env)
	      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)))))
    (setcdr key-slot info)))

(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
`set-langauge-info' for the meanings of KEY and INFO.

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)))
  (let ((describe-map describe-language-environment-map)
	(setup-map setup-language-environment-map))
    (if parents
	(let ((l parents)
	      map parent-symbol parent)
	  (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)))
	    (if (not map)
		(progn
		  (setq map (intern (format "describe-%s-environment-map"
					    (downcase parent))))
		  (define-prefix-command map)
		  (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))))
		  (define-prefix-command map)
		  (define-key-after setup-map (vector parent-symbol)
		    (cons parent map) t)))
	    (setq setup-map (symbol-value map))
	    (setq l (cdr l)))))

    ;; Set up menu items for this language env.
    (let ((doc (assq 'documentation alist))
	  (setup-function (assq 'setup-function alist)))
      (when doc
	(define-key-after describe-map (vector (intern lang-env))
	  (cons lang-env 'describe-specified-language-support) t))
      (when setup-function
	(define-key-after setup-map (vector (intern lang-env))
	  (cons lang-env 'setup-specified-language-environment) t)))

    (while alist
      (set-language-info lang-env (car (car alist)) (cdr (car alist)))
      (setq alist (cdr alist)))))

(defun read-language-name (key prompt &optional default)
  "Read a language environment name which has information for KEY.
Prompt with PROMPT.  DEFAULT is the default choice of language environment.
This returns a language environment name as a string."
  (let* ((completion-ignore-case t)
	 (name (completing-read prompt
				language-info-alist
				(function (lambda (elm) (assq key elm)))
				t nil nil default)))
    (if (and (> (length name) 0)
	     (get-language-info name key))
	name)))
\f
;;; Multilingual input methods.

(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.")

(defvar leim-list-header (format "\
;;; %s -- list of LEIM (Library of Emacs Input Method)
;;
;; This file contains a list of LEIM (Library of Emacs Input Method)
;; in the same directory as this file.  Loading this file registeres
;; the whole input methods in Emacs.
;;
;; Each entry has the form:
;;   (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.")

(defvar leim-list-entry-regexp "^(register-input-method"
  "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.")

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

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

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

(defcustom default-input-method nil
  "*Default input method for multilingual text (a string).
This is the input method activated automatically by the command
`toggle-input-method' (\\[toggle-input-method])."
  :group 'mule
  :type 'string)

(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)

(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.
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'.")
(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)

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

(defun register-input-method (input-method lang-env &rest args)
  "Register INPUT-METHOD as an input method for language environment ENV.
INPUT-METHOD and LANG-ENV are symbols or strings.

The remaining arguments are:
	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.
All told, the arguments to ACTIVATE-FUNC are INPUT-METHOD and the ARGS."
  (if (symbolp lang-env)
      (setq lang-env (symbol-name lang-env)))
  (if (symbolp input-method)
      (setq input-method (symbol-name input-method)))
  (let ((info (cons lang-env args))
	(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)))))

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

The return value is a string."
  (if default
      (setq prompt (format prompt default)))
  (let* ((completion-ignore-case t)
	 ;; This binding is necessary because input-method-history is
	 ;; buffer local.
	 (input-method (completing-read prompt input-method-alist
					nil t nil 'input-method-history
					default)))
    (if (> (length input-method) 0)
	input-method
      (if inhibit-null
	  (error "No valid input method is specified")))))

(defun activate-input-method (input-method)
  "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."
  (if (symbolp input-method)
      (setq input-method (symbol-name input-method)))
  (if (and current-input-method
	   (not (string= current-input-method input-method)))
    (inactivate-input-method))
  (unless (or current-input-method (null input-method))
    (let ((slot (assoc input-method input-method-alist)))
      (if (null slot)
	  (error "Can't activate input method `%s'" input-method))
      (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))))
      (setq current-input-method input-method)
      (setq current-input-method-title (nth 3 slot))
      (run-hooks 'input-method-activate-hook))))

(defun inactivate-input-method ()
  "Turn off the current input method."
  (when current-input-method
    (if input-method-history
	(unless (string= current-input-method (car input-method-history))
	  (setq input-method-history
		(cons current-input-method
		      (delete current-input-method input-method-history))))
      (setq input-method-history (list current-input-method)))
    (unwind-protect
	(funcall inactivate-current-input-method-function)
      (unwind-protect
	  (run-hooks 'input-method-inactivate-hook)
	(setq current-input-method nil
	      current-input-method-title nil)))))

(defun set-input-method (input-method)
  "Select and activate input method INPUT-METHOD for the current buffer.
This also sets the default input method to the one you specify."
  (interactive
   (let* ((default (or (car input-method-history) default-input-method)))
     (list (read-input-method-name
	    (if default "Select input method (default %s): " "Select input method: ")
	    default t))))
  (activate-input-method input-method)
  (setq default-input-method input-method))

(defun toggle-input-method (&optional arg)
  "Turn on or off a multilingual text input method for the current buffer.

With no prefix argument, if some input method is currently activated,
turn it off.  Otherwise, activate an input method--the one most recently used,
or the one specified in `default-input-method', or one read from the
minibuffer.

With a prefix arg, read an input method from minibuffer and turn it on.
The default is the most recent input method specified
\(not including the currently active input method, if any).

When there's no input method to turn on, turn on what read from minibuffer."
  (interactive "P")
  (if (and current-input-method (not arg))
      (inactivate-input-method)
    (let ((default (or (car input-method-history) default-input-method)))
      (if (and arg default (equal current-input-method default)
	       (> (length input-method-history) 1))
	  (setq default (nth 1 input-method-history)))
      (activate-input-method
       (if (or arg (not default))
	   (progn
	     (read-input-method-name
	      (if default "Input method (default %s): " "Input method: " )
	      default t))
	 default))
      (or default-input-method
	  (setq default-input-method current-input-method)))))

(defun describe-input-method (input-method)
  "Describe input method INPUT-METHOD."
  (interactive
   (list (read-input-method-name
	  "Describe input method (default, current choice): ")))
  (if (and input-method (symbolp input-method))
      (setq input-method (symbol-name input-method)))
  (if (null input-method)
      (describe-current-input-method)
    (with-output-to-temp-buffer "*Help*"
      (let ((elt (assoc input-method input-method-alist)))
	(princ (format "Input method: %s (`%s' in mode line) for %s\n  %s\n"
		       input-method (nth 3 elt) (nth 1 elt) (nth 4 elt)))))))

(defun describe-current-input-method ()
  "Describe the input method currently in use."
  (if current-input-method
      (if (and (symbolp describe-current-input-method-function)
	       (fboundp describe-current-input-method-function))
	  (funcall describe-current-input-method-function)
	(message "No way to describe the current input method `%s'"
		 (cdr current-input-method))
	(ding))
    (error "No input method is activated now")))

(defun read-multilingual-string (prompt &optional initial-input input-method)
  "Read a multilingual string from minibuffer, prompting with string PROMPT.
The input method selected last time is activated in minibuffer.
If optional second arg INITIAL-INPUT is non-nil, insert it in the minibuffer
initially.
Optional 3rd argument INPUT-METHOD specifies the input method
to be activated instead of the one selected last time.  It is a symbol
or a string."
  (setq input-method
	(or input-method
	    current-input-method
	    default-input-method
	    (read-input-method-name "Input method: " nil t)))
  (if (and input-method (symbolp input-method))
      (setq input-method (symbol-name input-method)))
  (let ((current-input-method input-method))
    (read-string prompt initial-input nil nil t)))

;; Variables to control behavior of input methods.  All input methods
;; should react to these variables.

(defcustom input-method-verbose-flag 'default
  "*A flag to control extra guidance given by input methods.
The value should be nil, t, `complex-only', or `default'.

The extra guidance is done by showing list of available keys in echo
area.  When you use the input method in the minibuffer, the guidance
is shown at the bottom short window (split from the existing window).

If the value is t, extra guidance is always given, if the value is
nil, extra guidance is always suppressed.

If the value is `complex-only', only complex input methods such as
`chinese-py' and `japanese' give extra guidance.

If the value is `default', complex input methods always give extra
guidance, but simple input methods give it only when you are not in
the minibuffer.

See also the variable `input-method-highlight-flag'."
  :type '(choice (const t) (const nil) (const complex-only) (const default))
  :group 'mule)

(defcustom input-method-highlight-flag t
  "*If this flag is non-nil, input methods highlight partially-entered text.
For instance, while you are in the middle of a Quail input method sequence,
the text inserted so far is temporarily underlined.
The underlining goes away when you finish or abort the input method sequence.
See also the variable `input-method-verbose-flag'."
  :type 'boolean
  :group 'mule)

(defvar input-method-activate-hook nil
  "Normal hook run just after an input method is activated.

The variable `current-input-method' keeps the input method name
just activated.")

(defvar input-method-inactivate-hook nil
  "Normal hook run just after an input method is inactivated.

The variable `current-input-method' still keeps the input method name
just inactivated.")

(defvar input-method-after-insert-chunk-hook nil
  "Normal hook run just after an input method insert some chunk of text.")

(defvar input-method-exit-on-invalid-key nil
  "This flag controls the behaviour of an input method on invalid key input.
Usually, when a user types a key which doesn't start any character
handled by the input method, the key is handled by turning off the
input method temporalily.  After the key is handled, the input method is 
back on.
But, if this flag is non-nil, the input method is never back on.")

\f
(defvar set-language-environment-hook nil
  "Normal hook run after some language environment is set.

When you set some hook function here, that effect usually should not
be inherited to another language environment.  So, you had better set
another function in `exit-language-environment-hook' (which see) to
cancel the effect.")

(defvar exit-language-environment-hook nil
  "Normal hook run after exiting from some language environment.
When this hook is run, the variable `current-language-environment'
is still bound to the language environment being exited.

This hook is mainly used for cancelling the effect of
`set-language-environment-hook' (which-see).")

(defun setup-specified-language-environment ()
  "Switch to a specified language environment."
  (interactive)
  (let (language-name)
    (if (and (symbolp last-command-event)
	     (or (not (eq last-command-event 'Default))
		 (setq last-command-event 'English))
	     (setq language-name (symbol-name last-command-event)))
	(set-language-environment language-name)
      (error "Bogus calling sequence"))))

(defcustom current-language-environment "English"
  "The last language environment specified with `set-language-environment'."
  :set 'set-language-environment
  :initialize 'custom-initialize-default
  :group 'mule
  :type 'string)

(defun set-language-environment (language-name)
  "Set up multi-lingual environment for using LANGUAGE-NAME.
This sets the coding system priority and the default input method
and sometimes other things.  LANGUAGE-NAME should be a string
which is the name of a language environment.  For example, \"Latin-1\"
specifies the character set for the major languages of Western Europe."
  (interactive (list (read-language-name
		      'setup-function
		      "Set language environment (default, English): ")))
  (if language-name
      (if (symbolp language-name)
	  (setq language-name (symbol-name language-name)))
    (setq language-name "English"))
  (if (null (get-language-info language-name 'setup-function))
      (error "Language environment not defined: %S" language-name))
  (if current-language-environment
      (let ((func (get-language-info current-language-environment
				     'exit-function)))
	(run-hooks 'exit-language-environment-hook)
	(if (fboundp func) (funcall func))))
  (when (and (not default-enable-multibyte-characters)
	     (get-language-info language-name 'unibyte-syntax))
    (set-terminal-coding-system (intern (downcase language-name)))
    (standard-display-european-internal))
  (setq current-language-environment language-name)
  (funcall (get-language-info language-name 'setup-function))
  (run-hooks 'set-language-environment-hook)
  (force-mode-line-update t))

(defun standard-display-european-internal ()
  ;; Actually set up direct output of non-ASCII characters.
  (standard-display-8bit 160 255)
  ;; Make non-line-break space display as a plain space.
  ;; Most X fonts do the wrong thing for code 160.
  (aset standard-display-table 160 [32])
  ;; Most Windows programs send out apostrophe's as \222.  Most X fonts
  ;; don't contain a character at that position.  Map it to the ASCII
  ;; apostrophe.
  (aset standard-display-table 146 [39]))

(defun set-language-environment-coding-systems (language-name)
  "Do various coding system setups for language environment LANGUAGE-NAME."
  (let* ((priority (get-language-info language-name 'coding-priority))
	 (default-coding (car priority)))
    (if priority
	(let ((categories (mapcar 'coding-system-category priority)))
	  (set-default-coding-systems default-coding)
	  (set-coding-priority categories)
	  (while priority
	    (set (car categories) (car priority))
	    (setq priority (cdr priority) categories (cdr categories)))
	  (update-iso-coding-systems)))))

;; Print all arguments with `princ', then print "\n".
(defsubst princ-list (&rest args)
  (while args (princ (car args)) (setq args (cdr args)))
  (princ "\n"))

;; Print a language specific information such as input methods,
;; charsets, and coding systems.  This function is intended to be
;; called from the menu:
;;   [menu-bar mule describe-language-environment LANGUAGE]
;; and should not run it by `M-x describe-current-input-method-function'.
(defun describe-specified-language-support ()
  "Describe how Emacs supports the specified language environment."
  (interactive)
  (let (language-name)
    (if (not (and (symbolp last-command-event)
		  (setq language-name (symbol-name last-command-event))))
	(error "Bogus calling sequence"))
    (describe-language-environment language-name)))

(defun describe-language-environment (language-name)
  "Describe how Emacs supports language environment LANGUAGE-NAME."
  (interactive
   (list (read-language-name
	  'documentation
	  "Describe language environment (default, current choice): ")))
  (if (null language-name)
      (setq language-name current-language-environment))
  (if (or (null language-name)
	  (null (get-language-info language-name 'documentation)))
      (error "No documentation for the specified language"))
  (if (symbolp language-name)
      (setq language-name (symbol-name language-name)))
  (let ((doc (get-language-info language-name 'documentation)))
    (with-output-to-temp-buffer "*Help*"
      (princ-list language-name " language environment" "\n")
      (if (stringp doc)
	  (progn
	    (princ-list doc)
	    (terpri)))
      (let ((str (get-language-info language-name 'sample-text)))
	(if (stringp str)
	    (progn
	      (princ "Sample text:\n")
	      (princ-list "  " str)
	      (terpri))))
      (princ "Input methods:\n")
      (let ((l input-method-alist))
	(while l
	  (if (string= language-name (nth 1 (car l)))
	      (princ-list "  " (car (car l))
			  (format " (`%s' in mode line)" (nth 3 (car l)))))
	  (setq l (cdr l))))
      (terpri)
      (princ "Character sets:\n")
      (let ((l (get-language-info language-name 'charset)))
	(if (null l)
	    (princ-list "  nothing specific to " language-name)
	  (while l
	    (princ-list "  " (car l) ": "
			(charset-description (car l)))
	    (setq l (cdr l)))))
      (terpri)
      (princ "Coding systems:\n")
      (let ((l (get-language-info language-name 'coding-system)))
	(if (null l)
	    (princ-list "  nothing specific to " language-name)
	  (while l
	    (princ (format "  %s (`%c' in mode line):\n\t%s\n"
			   (car l)
			   (coding-system-mnemonic (car l))
			   (coding-system-doc-string (car l))))
	    (let ((aliases (coding-system-get (car l) 'alias-coding-systems)))
	      (when aliases
		(princ "\t")
		(princ (cons 'alias: (cdr aliases)))
		(terpri)))
	    (setq l (cdr l))))))))
\f
;;; Charset property

(defsubst get-charset-property (charset propname)
  "Return the value of CHARSET's PROPNAME property.
This is the last value stored with
 (put-charset-property CHARSET PROPNAME VALUE)."
  (plist-get (charset-plist charset) propname))

(defsubst put-charset-property (charset propname value)
  "Store CHARSETS's PROPNAME property with value VALUE.
It can be retrieved with `(get-charset-property CHARSET PROPNAME)'."
  (set-charset-plist charset
		     (plist-put (charset-plist charset) propname value)))

;;; Character code property
(put 'char-code-property-table 'char-table-extra-slots 0)

(defvar char-code-property-table
  (make-char-table 'char-code-property-table)
  "Char-table containing a property list of each character code.

See also the documentation of `get-char-code-property' and
`put-char-code-property'.")

(defun get-char-code-property (char propname)
  "Return the value of CHAR's PROPNAME property in `char-code-property-table'."
  (let ((plist (aref char-code-property-table char)))
    (if (listp plist)
	(car (cdr (memq propname plist))))))

(defun put-char-code-property (char propname value)
  "Store CHAR's PROPNAME property with VALUE in `char-code-property-table'.
It can be retrieved with `(get-char-code-property CHAR PROPNAME)'."
  (let ((plist (aref char-code-property-table char)))
    (if plist
	(let ((slot (memq propname plist)))
	  (if slot
	      (setcar (cdr slot) value)
	    (nconc plist (list propname value))))
      (aset char-code-property-table char (list propname value)))))

;;; mule-cmds.el ends here