;;; iso-transl.el --- keyboard input for ISO 10646 chars -*- coding: utf-8; lexical-binding: t; -*-

;; Copyright (C) 1987, 1993-1999, 2001-2021 Free Software Foundation,
;; Inc.

;; Author: Howard Gayle
;; Maintainer: emacs-devel@gnu.org
;; Keywords: i18n

;; 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 3 of the License, 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.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; Loading this package defines three ways of entering the non-ASCII
;; printable characters with codes above 127: the prefix C-x 8, or the
;; Alt key, or a dead accent key.  For example, you can enter uppercase
;; A-umlaut as `C-x 8 " A' or `Alt-" A' (if you have an Alt key) or
;; `umlaut A' (if you have an umlaut/diaeresis key).

;; This package supports all characters defined by ISO 8859-1, along
;; with a few other ISO 10646 characters commonly used in English and
;; basic math.

;;; Code:

(defvar iso-transl-dead-key-alist
  '((?\' . mute-acute)
    (?\` . mute-grave)
    (?\" . mute-diaeresis)
    (?^ . mute-asciicircum)
    (?\~ . mute-asciitilde)
    (?\' . dead-acute)
    (?\` . dead-grave)
    (?\" . dead-diaeresis)
    (?^ . dead-asciicircum)
    (?\~ . dead-asciitilde)
    (?^ . dead-circum)
    (?^ . dead-circumflex)
    (?\~ . dead-tilde)
    ;; Someone reports that these keys don't work if shifted.
    ;; This might fix it--no word yet.
    (?\' . S-dead-acute)
    (?\` . S-dead-grave)
    (?\" . S-dead-diaeresis)
    (?^ . S-dead-asciicircum)
    (?\~ . S-dead-asciitilde)
    (?^ . S-dead-circum)
    (?^ . S-dead-circumflex)
    (?\~ . S-dead-tilde))
  "Mapping of ASCII characters to their corresponding dead-key symbols.")

;; The two-character mnemonics are intended to be available in all languages.
;; The ones beginning with `*' have one-character synonyms, but a
;; language-specific table might override the short form for its own use.

(defvar iso-transl-char-map
  '(("* "   . [? ])
    (" "    . [? ])
    ("*!"   . [?¡])
    ("!"    . [?¡])
    ("\"\"" . [?¨])
    ("\"A"  . [?Ä])
    ("\"E"  . [?Ë])
    ("\"I"  . [?Ï])
    ("\"O"  . [?Ö])
    ("\"U"  . [?Ü])
    ("\"a"  . [?ä])
    ("\"e"  . [?ë])
    ("\"i"  . [?ï])
    ("\"o"  . [?ö])
    ("\"s"  . [?ß])
    ("\"u"  . [?ü])
    ("\"y"  . [?ÿ])
    ("''"   . [?´])
    ("'A"   . [?Á])
    ("'E"   . [?É])
    ("'I"   . [?Í])
    ("'O"   . [?Ó])
    ("'U"   . [?Ú])
    ("'Y"   . [?Ý])
    ("'a"   . [?á])
    ("'e"   . [?é])
    ("'i"   . [?í])
    ("'o"   . [?ó])
    ("'u"   . [?ú])
    ("'y"   . [?ý])
    ("*$"   . [?¤])
    ("$"    . [?¤])
    ("*+"   . [?±])
    ("+"    . [?±])
    (",,"   . [?¸])
    (",C"   . [?Ç])
    (",c"   . [?ç])
    ("*-"   . [?­])
    ("-"    . [?­])
    ("*."   . [?·])
    ("."    . [?·])
    ("//"   . [?÷])
    ("/A"   . [?Å])
    ("/E"   . [?Æ])
    ("/O"   . [?Ø])
    ("/a"   . [?å])
    ("/e"   . [?æ])
    ("/o"   . [?ø])
    ("1/2"  . [?½])
    ("1/4"  . [?¼])
    ("3/4"  . [?¾])
    ("*<"   . [?«])
    ("<"    . [?«])
    ("*="   . [?¯])
    ("="    . [?¯])
    ("*>"   . [?»])
    (">"    . [?»])
    ("*?"   . [?¿])
    ("?"    . [?¿])
    ("*C"   . [?©])
    ("C"    . [?©])
    ("*L"   . [?£])
    ("L"    . [?£])
    ("*P"   . [?¶])
    ("P"    . [?¶])
    ("*R"   . [?®])
    ("R"    . [?®])
    ("*S"   . [?§])
    ("S"    . [?§])
    ("*Y"   . [?¥])
    ("Y"    . [?¥])
    ("^1"   . [?¹])
    ("^2"   . [?²])
    ("^3"   . [?³])
    ("^A"   . [?Â])
    ("^E"   . [?Ê])
    ("^I"   . [?Î])
    ("^O"   . [?Ô])
    ("^U"   . [?Û])
    ("^a"   . [?â])
    ("^e"   . [?ê])
    ("^i"   . [?î])
    ("^o"   . [?ô])
    ("^u"   . [?û])
    ("_a"   . [?ª])
    ("_o"   . [?º])
    ("`A"   . [?À])
    ("`E"   . [?È])
    ("`I"   . [?Ì])
    ("`O"   . [?Ò])
    ("`U"   . [?Ù])
    ("`a"   . [?à])
    ("`e"   . [?è])
    ("`i"   . [?ì])
    ("`o"   . [?ò])
    ("`u"   . [?ù])
    ("*c"   . [?¢])
    ("c"    . [?¢])
    ("*o"   . [?°])
    ("o"    . [?°])
    ("Oe"   . [?œ])
    ("OE"   . [?Œ])
    ("*u"   . [?µ])
    ("u"    . [?µ])
    ("*m"   . [?µ])
    ("m"    . [?µ])
    ("*x"   . [?×])
    ("x"    . [?×])
    ("*|"   . [?¦])
    ("|"    . [?¦])
    ("~A"   . [?Ã])
    ("~D"   . [?Ð])
    ("~N"   . [?Ñ])
    ("~O"   . [?Õ])
    ("~T"   . [?Þ])
    ("~a"   . [?ã])
    ("~d"   . [?ð])
    ("~n"   . [?ñ])
    ("~o"   . [?õ])
    ("~t"   . [?þ])
    ("~~"   . [?¬])
    ("_h"   . [?‐])
    ("_H"   . [?‑])
    ("_f"   . [?‒])
    ("_n"   . [?–])
    ("_m"   . [?—])
    ("_q"   . [?―])
    ("["    . [?‘])
    ("]"    . [?’])
    ("{"    . [?“])
    ("}"    . [?”])
    ("1+"   . [?†])
    ("2+"   . [?‡])
    ("**"   . [?•])
    ("*'"   . [?′])
    ("*\""  . [?″])
    ("*E"   . [?€])
    ("No"   . [?№])
    ("a<"   . [?←])
    ("a>"   . [?→])
    ("a="   . [?↔])
    ("_-"   . [?−])
    ("~="   . [?≈])
    ("/="   . [?≠])
    ("_<"   . [?≤])
    ("_>"   . [?≥])
    ("' "   . "'")
    ("` "   . "`")
    ("\" "  . "\"")
    ("^ "   . "^")
    ("~ "   . "~"))
  "Alist of character translations for entering ISO characters.
Each element has the form (STRING . VECTOR).
The sequence STRING of ASCII chars translates into the
sequence VECTOR.  (VECTOR is normally one character long.)")

;; Language-specific translation lists.
(defvar iso-transl-language-alist
  '(("Esperanto"
     ("C"  . [?Ĉ])
     ("G"  . [?Ĝ])
     ("H"  . [?Ĥ])
     ("J"  . [?Ĵ])
     ("S"  . [?Ŝ])
     ("U"  . [?Ŭ])
     ("c"  . [?ĉ])
     ("g"  . [?ĝ])
     ("h"  . [?ĥ])
     ("j"  . [?ĵ])
     ("s"  . [?ŝ])
     ("u"  . [?ŭ]))
    ("French"
     ("C"  . [?Ç])
     ("c"  . [?ç]))
    ("German"
     ("A"  . [?Ä])
     ("O"  . [?Ö])
     ("U"  . [?Ü])
     ("a"  . [?ä])
     ("o"  . [?ö])
     ("s"  . [?ß])
     ("u"  . [?ü]))
    ("Portuguese"
     ("C"  . [?Ç])
     ("c"  . [?ç]))
    ("Spanish"
     ("!"  . [?¡])
     ("?"  . [?¿])
     ("N"  . [?Ñ])
     ("n"  . [?ñ]))))

(defvar iso-transl-ctl-x-8-map nil
  "Keymap for C-x 8 prefix.")
(or iso-transl-ctl-x-8-map
    (fset 'iso-transl-ctl-x-8-map
	  (setq iso-transl-ctl-x-8-map (make-sparse-keymap))))
(or key-translation-map
    (setq key-translation-map (make-sparse-keymap)))
(define-key key-translation-map "\C-x8" iso-transl-ctl-x-8-map)

;; For each entry in the alist, we'll make up to three ways to generate
;; the character in question: the prefix `C-x 8'; the ALT modifier on
;; the first key of the sequence; and (if applicable) replacing the first
;; key of the sequence with the corresponding dead key.  For example, a
;; character associated with the string "~n" can be input with `C-x 8 ~ n'
;; or `Alt-~ n' or `mute-asciitilde n'.
(defun iso-transl-define-keys (alist)
  (while alist
    (let ((translated-vec (cdr (car alist))))
      (define-key iso-transl-ctl-x-8-map (car (car alist)) translated-vec)
      (let ((inchar (aref (car (car alist)) 0))
	    (vec (vconcat (car (car alist))))
	    (tail iso-transl-dead-key-alist))
	(aset vec 0 (logior (aref vec 0) ?\A-\^@))
	(define-key key-translation-map vec translated-vec)
	(define-key isearch-mode-map (vector (aref vec 0)) nil)
	(while tail
	  (if (eq (car (car tail)) inchar)
	      (let ((deadvec (copy-sequence vec))
		    (deadkey (cdr (car tail))))
		(aset deadvec 0 deadkey)
		(define-key isearch-mode-map (vector deadkey) nil)
		(define-key key-translation-map deadvec translated-vec)))
	  (setq tail (cdr tail)))))
    (setq alist (cdr alist))))

(defun iso-transl-set-language (lang)
  (interactive (list (let ((completion-ignore-case t))
		       (completing-read "Set which language? "
					iso-transl-language-alist nil t))))
  (iso-transl-define-keys (cdr (assoc lang iso-transl-language-alist))))


;; The standard mapping comes automatically.  You can partially overlay it
;; with a language-specific mapping by using `M-x iso-transl-set-language'.
(iso-transl-define-keys iso-transl-char-map)

(provide 'iso-transl)

;;; iso-transl.el ends here