lisp/international/latexenc.el

   1 ;;; latexenc.el --- guess correct coding system in LaTeX files -*-coding: iso-2022-7bit -*-
   2
   3 ;; Copyright (C) 2005, 2006 Free Software Foundation, Inc.
   4
   5 ;; Author: Arne J\e,Ax\e(Brgensen <arne@arnested.dk>
   6 ;; Keywords: mule, coding system, latex
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  22 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  23 ;; Boston, MA 02110-1301, USA.
  24
  25 ;;; Commentary:
  26
  27 ;; This code tries to guess the correct coding system of a LaTeX file.
  28
  29 ;; First it searches for a \inputencoding{...} or
  30 ;; \usepackage[...]{inputenc} line in the file and looks up the ... in
  31 ;; `latex-inputenc-coding-alist' to find the corresponding coding
  32 ;; system.
  33
  34 ;; If this fails it will search for AUCTeX's TeX-master or tex-mode's
  35 ;; tex-main-file variable in the local variables section and visit
  36 ;; that file to get the coding system from the master file. This check
  37 ;; can be disabled by setting `latexenc-dont-use-TeX-master-flag' to
  38 ;; t.
  39
  40 ;; If we have still not found a coding system we will try to use the
  41 ;; standard tex-mode's `tex-guess-main-file' and get the coding system
  42 ;; from the main file. This check can be disabled by setting
  43 ;; `latexenc-dont-use-tex-guess-main-file-flag' to t.
  44
  45 ;; The functionality is enabled by adding the function
  46 ;; `latexenc-find-file-coding-system' to `file-coding-system-alist'
  47 ;; like this
  48
  49 ;; (add-to-list 'file-coding-system-alist
  50 ;;           '("\\.\\(tex\\|ltx\\|dtx\\|drv\\)\\'" . latexenc-find-file-coding-system))
  51
  52 ;;; Code:
  53
  54 ;;;###autoload
  55 (defcustom latex-inputenc-coding-alist
  56   '(("ansinew" . windows-1252) ; MS Windows ANSI encoding, extension of Latin-1
  57     ("applemac" . mac-roman)
  58     ("ascii" . us-ascii)
  59     ("cp1250" . windows-1250) ; MS Windows encoding, codepage 1250
  60     ("cp1252" . windows-1252) ; synonym of ansinew
  61     ("cp1257" . cp1257)
  62     ("cp437de" . cp437) ; IBM code page 437 (German version): 225 is \ss
  63     ("cp437" . cp437) ; IBM code page 437: 225 is \beta
  64     ("cp850" . cp850) ; IBM code page 850
  65     ("cp852" . cp852) ; IBM code page 852
  66     ("cp858" . cp858) ; IBM code page 850 but with a euro symbol
  67     ("cp865" . cp865) ; IBM code page 865
  68     ;; The DECMultinational charaterset used by the OpenVMS system
  69     ;; ("decmulti" . undecided)
  70     ("latin1" . iso-8859-1)
  71     ("latin2" . iso-8859-2)
  72     ("latin3" . iso-8859-3)
  73     ("latin4" . iso-8859-4)
  74     ("latin5" . iso-8859-5)
  75     ("latin9" . iso-8859-15)
  76     ;; ("latin10" . undecided)
  77     ;; ("macce" . undecided) ; Apple Central European
  78     ("next" . next) ; The Next encoding
  79     ("utf8" . utf-8)
  80     ("utf8x" . utf-8)) ; used by the Unicode LaTeX package
  81   "Mapping from LaTeX encodings in \"inputenc.sty\" to Emacs coding systems.
  82 LaTeX encodings are specified with \"\\usepackage[encoding]{inputenc}\".
  83 Used by the function `latexenc-find-file-coding-system'."
  84   :group 'files
  85   :group 'mule
  86   :type '(alist :key-type (string :tag "LaTeX input encoding")
  87                 :value-type (coding-system :tag "Coding system")))
  88
  89 ;;;###autoload
  90 (defun latexenc-inputenc-to-coding-system (inputenc)
  91   "Return the corresponding coding-system for the specified input encoding.
  92 Return nil if no matching coding system can be found."
  93   (cdr (assoc inputenc latex-inputenc-coding-alist)))
  94
  95 ;;;###autoload
  96 (defun latexenc-coding-system-to-inputenc (cs)
  97   "Return the corresponding input encoding for the specified coding system.
  98 Return nil if no matching input encoding can be found."
  99   (let (result)
 100     (catch 'result
 101       (dolist (elem latex-inputenc-coding-alist result)
 102         (let ((elem-cs (cdr elem)))
 103           (when (and (coding-system-p elem-cs)
 104                      (coding-system-p cs)
 105                      (eq (coding-system-base cs) (coding-system-base elem-cs)))
 106             (setq result (car elem))
 107             (throw 'result result)))))))
 108
 109 (defvar latexenc-dont-use-TeX-master-flag nil
 110   "Non-nil means don't follow TeX-master to find the coding system.")
 111
 112 (defvar latexenc-dont-use-tex-guess-main-file-flag nil
 113   "Non-nil means don't use tex-guessmain-file to find the coding system.")
 114
 115 ;;;###autoload
 116 (defun latexenc-find-file-coding-system (arg-list)
 117   "Determine the coding system of a LaTeX file if it uses \"inputenc.sty\".
 118 The mapping from LaTeX's \"inputenc.sty\" encoding names to Emacs
 119 coding system names is determined from `latex-inputenc-coding-alist'."
 120   (if (eq (car arg-list) 'insert-file-contents)
 121       (save-excursion
 122         ;; try to find the coding system in this file
 123         (goto-char (point-min))
 124         (if (catch 'cs
 125               (let ((case-fold-search nil))
 126                 (while (search-forward "inputenc" nil t)
 127                   (goto-char (match-beginning 0))
 128                   (beginning-of-line)
 129                   (if (or (looking-at "[^%\n]*\\\\usepackage\\[\\([^]]*\\)\\]{\\([^}]*,\\)?inputenc\\(,[^}]*\\)?}")
 130                           (looking-at "[^%\n]*\\\\inputencoding{\\([^}]*\\)}"))
 131                       (throw 'cs t)
 132                     (goto-char (match-end 0))))))
 133             (let* ((match (match-string 1))
 134                    (sym (or (latexenc-inputenc-to-coding-system match)
 135                             (intern match))))
 136               (cond
 137                ((coding-system-p sym) sym)
 138                ((and (require 'code-pages nil t) (coding-system-p sym)) sym)
 139                (t 'undecided)))
 140           ;; else try to find it in the master/main file
 141
 142           ;; Fixme: If the current file is in an archive (e.g. tar,
 143           ;; zip), we should find the master file in that archive.
 144           ;; But, that is not yet implemented.   -- K.Handa
 145           (let ((default-directory (if (stringp (nth 1 arg-list))
 146                                        (file-name-directory (nth 1 arg-list))
 147                                      default-directory))
 148                 latexenc-main-file)
 149             ;; Is there a TeX-master or tex-main-file in the local variables
 150             ;; section?
 151             (unless latexenc-dont-use-TeX-master-flag
 152               (goto-char (point-max))
 153               (search-backward "\n\^L" (max (- (point-max) 3000) (point-min))
 154                                'move)
 155               (search-forward "Local Variables:" nil t)
 156               (when (re-search-forward
 157                      "^%+ *\\(TeX-master\\|tex-main-file\\): *\"\\(.+\\)\""
 158                      nil t)
 159                 (let ((file (match-string 2)))
 160                   (dolist (ext `("" ,(if (boundp 'TeX-default-extension)
 161                                          (concat "." TeX-default-extension)
 162                                        "")
 163                                  ".tex" ".ltx" ".dtx" ".drv"))
 164                     (if (and (null latexenc-main-file) ;Stop at first.
 165                              (file-exists-p (concat file ext)))
 166                         (setq latexenc-main-file (concat file ext)))))))
 167             ;; try tex-modes tex-guess-main-file
 168             (when (and (not latexenc-dont-use-tex-guess-main-file-flag)
 169                        (not latexenc-main-file))
 170               ;; Use a separate `when' so the byte-compiler sees the fboundp.
 171               (when (fboundp 'tex-guess-main-file)
 172                 (let ((tex-start-of-header "\\\\document\\(style\\|class\\)"))
 173                   (setq latexenc-main-file (tex-guess-main-file)))))
 174             ;; if we found a master/main file get the coding system from it
 175             (if (and latexenc-main-file
 176                      (file-regular-p latexenc-main-file)
 177                      (file-readable-p latexenc-main-file))
 178                 (let* ((latexenc-dont-use-tex-guess-main-file-flag t)
 179                        (latexenc-dont-use-TeX-master-flag t)
 180                        (latexenc-main-buffer
 181                         (find-file-noselect latexenc-main-file t)))
 182                   (coding-system-base   ;Disregard the EOL part of the CS.
 183                    (with-current-buffer latexenc-main-buffer
 184                      (or coding-system-for-write buffer-file-coding-system))))
 185               'undecided))))
 186     'undecided))
 187
 188 \f
 189 (provide 'latexenc)
 190
 191 ;; arch-tag: f971bc3e-1fec-4609-8f2f-73dd41ab22e1
 192 ;;; latexenc.el ends here