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[emacs.git] / lisp / international / latexenc.el
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1 ;;; latexenc.el --- guess correct coding system in LaTeX files -*-coding: utf-8 -*-
3 ;; Copyright (C) 2005-2017 Free Software Foundation, Inc.
5 ;; Author: Arne Jørgensen <arne@arnested.dk>
6 ;; Keywords: mule, coding system, latex
8 ;; This file is part of GNU Emacs.
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 3 of the License, or
13 ;; (at your option) any later version.
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.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
23 ;;; Commentary:
25 ;; This code tries to guess the correct coding system of a LaTeX file.
27 ;; First it searches for a \inputencoding{...} or
28 ;; \usepackage[...]{inputenc} line in the file and looks up the ... in
29 ;; `latex-inputenc-coding-alist' to find the corresponding coding
30 ;; system.
32 ;; If this fails it will search for AUCTeX's TeX-master or tex-mode's
33 ;; tex-main-file variable in the local variables section and visit
34 ;; that file to get the coding system from the master file. This check
35 ;; can be disabled by setting `latexenc-dont-use-TeX-master-flag' to
36 ;; t.
38 ;; If we have still not found a coding system we will try to use the
39 ;; standard tex-mode's `tex-guess-main-file' and get the coding system
40 ;; from the main file. This check can be disabled by setting
41 ;; `latexenc-dont-use-tex-guess-main-file-flag' to t.
43 ;; The functionality is enabled by adding the function
44 ;; `latexenc-find-file-coding-system' to `file-coding-system-alist'
45 ;; like this
47 ;; (add-to-list 'file-coding-system-alist
48 ;; '("\\.\\(tex\\|ltx\\|dtx\\|drv\\)\\'" . latexenc-find-file-coding-system))
50 ;;; Code:
52 ;;;###autoload
53 (defcustom latex-inputenc-coding-alist
54 (purecopy
55 '(("ansinew" . windows-1252) ; MS Windows ANSI encoding, extension of Latin-1
56 ("applemac" . mac-roman)
57 ("ascii" . us-ascii)
58 ("cp1250" . windows-1250) ; MS Windows encoding, codepage 1250
59 ("cp1252" . windows-1252) ; synonym of ansinew
60 ("cp1257" . cp1257)
61 ("cp437de" . cp437) ; IBM code page 437 (German version): 225 is \ss
62 ("cp437" . cp437) ; IBM code page 437: 225 is \beta
63 ("cp850" . cp850) ; IBM code page 850
64 ("cp852" . cp852) ; IBM code page 852
65 ("cp858" . cp858) ; IBM code page 850 but with a euro symbol
66 ("cp865" . cp865) ; IBM code page 865
67 ("latin1" . iso-8859-1)
68 ("latin2" . iso-8859-2)
69 ("latin3" . iso-8859-3)
70 ("latin4" . iso-8859-4)
71 ("latin5" . iso-8859-5)
72 ("latin9" . iso-8859-15)
73 ;; ("latin10" . undecided)
74 ;; ("macce" . undecided) ; Apple Central European
75 ("next" . next) ; The Next encoding
76 ("utf8" . utf-8)
77 ("utf8x" . utf-8))) ; used by the Unicode LaTeX package
78 "Mapping from LaTeX encodings in \"inputenc.sty\" to Emacs coding systems.
79 LaTeX encodings are specified with \"\\usepackage[encoding]{inputenc}\".
80 Used by the function `latexenc-find-file-coding-system'."
81 :group 'files
82 :group 'mule
83 :type '(alist :key-type (string :tag "LaTeX input encoding")
84 :value-type (coding-system :tag "Coding system")))
86 ;;;###autoload
87 (defun latexenc-inputenc-to-coding-system (inputenc)
88 "Return the corresponding coding-system for the specified input encoding.
89 Return nil if no matching coding system can be found."
90 (cdr (assoc inputenc latex-inputenc-coding-alist)))
92 ;;;###autoload
93 (defun latexenc-coding-system-to-inputenc (cs)
94 "Return the corresponding input encoding for the specified coding system.
95 Return nil if no matching input encoding can be found."
96 (let (result)
97 (catch 'result
98 (dolist (elem latex-inputenc-coding-alist result)
99 (let ((elem-cs (cdr elem)))
100 (when (and (coding-system-p elem-cs)
101 (coding-system-p cs)
102 (eq (coding-system-base cs) (coding-system-base elem-cs)))
103 (setq result (car elem))
104 (throw 'result result)))))))
106 (defvar latexenc-dont-use-TeX-master-flag nil
107 "Non-nil means don't follow TeX-master to find the coding system.")
109 (defvar latexenc-dont-use-tex-guess-main-file-flag nil
110 "Non-nil means don't use tex-guessmain-file to find the coding system.")
112 ;;;###autoload
113 (defun latexenc-find-file-coding-system (arg-list)
114 "Determine the coding system of a LaTeX file if it uses \"inputenc.sty\".
115 The mapping from LaTeX's \"inputenc.sty\" encoding names to Emacs
116 coding system names is determined from `latex-inputenc-coding-alist'."
117 (if (eq (car arg-list) 'insert-file-contents)
118 (save-excursion
119 ;; try to find the coding system in this file
120 (goto-char (point-min))
121 (if (catch 'cs
122 (let ((case-fold-search nil))
123 (while (search-forward "inputenc" nil t)
124 (goto-char (match-beginning 0))
125 (beginning-of-line)
126 (if (or (looking-at "[^%\n]*\\\\usepackage\\[\\([^]]*\\)\\]{\\([^}]*,\\)?inputenc\\(,[^}]*\\)?}")
127 (looking-at "[^%\n]*\\\\inputencoding{\\([^}]*\\)}"))
128 (throw 'cs t)
129 (goto-char (match-end 0))))))
130 (let* ((match (match-string 1))
131 (sym (or (latexenc-inputenc-to-coding-system match)
132 (intern match))))
133 (cond
134 ((coding-system-p sym) sym)
135 ((and (require 'code-pages nil t) (coding-system-p sym)) sym)
136 (t 'undecided)))
137 ;; else try to find it in the master/main file
139 ;; Fixme: If the current file is in an archive (e.g. tar,
140 ;; zip), we should find the master file in that archive.
141 ;; But, that is not yet implemented. -- K.Handa
142 (let ((default-directory (if (stringp (nth 1 arg-list))
143 (file-name-directory (nth 1 arg-list))
144 default-directory))
145 latexenc-main-file)
146 ;; Is there a TeX-master or tex-main-file in the local variables
147 ;; section?
148 (unless latexenc-dont-use-TeX-master-flag
149 (goto-char (point-max))
150 (search-backward "\n\^L" (max (- (point-max) 3000) (point-min))
151 'move)
152 (search-forward "Local Variables:" nil t)
153 (when (re-search-forward
154 "^%+ *\\(TeX-master\\|tex-main-file\\): *\"\\(.+\\)\""
155 nil t)
156 (let ((file (match-string 2)))
157 (dolist (ext `("" ,(if (boundp 'TeX-default-extension)
158 (concat "." TeX-default-extension)
160 ".tex" ".ltx" ".dtx" ".drv"))
161 (if (and (null latexenc-main-file) ;Stop at first.
162 (file-exists-p (concat file ext)))
163 (setq latexenc-main-file (concat file ext)))))))
164 ;; try tex-modes tex-guess-main-file
165 (when (and (not latexenc-dont-use-tex-guess-main-file-flag)
166 (not latexenc-main-file))
167 ;; Use a separate `when' so the byte-compiler sees the fboundp.
168 (when (fboundp 'tex-guess-main-file)
169 (let ((tex-start-of-header "\\\\document\\(style\\|class\\)"))
170 (setq latexenc-main-file (tex-guess-main-file)))))
171 ;; if we found a master/main file get the coding system from it
172 (if (and latexenc-main-file
173 (file-regular-p latexenc-main-file)
174 (file-readable-p latexenc-main-file))
175 (let* ((latexenc-dont-use-tex-guess-main-file-flag t)
176 (latexenc-dont-use-TeX-master-flag t)
177 (latexenc-main-buffer
178 (find-file-noselect latexenc-main-file t)))
179 (coding-system-base ;Disregard the EOL part of the CS.
180 (with-current-buffer latexenc-main-buffer
181 (or coding-system-for-write buffer-file-coding-system
182 'undecided))))
183 'undecided))))
184 'undecided))
187 (provide 'latexenc)
189 ;;; latexenc.el ends here