summaryrefslogtreecommitdiff
path: root/lisp/international/latexenc.el
blob: c39162a236f2c76e612d4ea4c7ed3764eeb88e27 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
;;; latexenc.el --- guess correct coding system in LaTeX files -*-coding: utf-8 -*-

;; Copyright (C) 2005-2016 Free Software Foundation, Inc.

;; Author: Arne Jørgensen <arne@arnested.dk>
;; Keywords: mule, coding system, latex

;; 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 <http://www.gnu.org/licenses/>.

;;; Commentary:

;; This code tries to guess the correct coding system of a LaTeX file.

;; First it searches for a \inputencoding{...} or
;; \usepackage[...]{inputenc} line in the file and looks up the ... in
;; `latex-inputenc-coding-alist' to find the corresponding coding
;; system.

;; If this fails it will search for AUCTeX's TeX-master or tex-mode's
;; tex-main-file variable in the local variables section and visit
;; that file to get the coding system from the master file. This check
;; can be disabled by setting `latexenc-dont-use-TeX-master-flag' to
;; t.

;; If we have still not found a coding system we will try to use the
;; standard tex-mode's `tex-guess-main-file' and get the coding system
;; from the main file. This check can be disabled by setting
;; `latexenc-dont-use-tex-guess-main-file-flag' to t.

;; The functionality is enabled by adding the function
;; `latexenc-find-file-coding-system' to `file-coding-system-alist'
;; like this

;; (add-to-list 'file-coding-system-alist
;; 	     '("\\.\\(tex\\|ltx\\|dtx\\|drv\\)\\'" . latexenc-find-file-coding-system))

;;; Code:

;;;###autoload
(defcustom latex-inputenc-coding-alist
  (purecopy
  '(("ansinew" . windows-1252) ; MS Windows ANSI encoding, extension of Latin-1
    ("applemac" . mac-roman)
    ("ascii" . us-ascii)
    ("cp1250" . windows-1250) ; MS Windows encoding, codepage 1250
    ("cp1252" . windows-1252) ; synonym of ansinew
    ("cp1257" . cp1257)
    ("cp437de" . cp437) ; IBM code page 437 (German version): 225 is \ss
    ("cp437" . cp437) ; IBM code page 437: 225 is \beta
    ("cp850" . cp850) ; IBM code page 850
    ("cp852" . cp852) ; IBM code page 852
    ("cp858" . cp858) ; IBM code page 850 but with a euro symbol
    ("cp865" . cp865) ; IBM code page 865
    ("latin1" . iso-8859-1)
    ("latin2" . iso-8859-2)
    ("latin3" . iso-8859-3)
    ("latin4" . iso-8859-4)
    ("latin5" . iso-8859-5)
    ("latin9" . iso-8859-15)
    ;; ("latin10" . undecided)
    ;; ("macce" . undecided) ; Apple Central European
    ("next" . next) ; The Next encoding
    ("utf8" . utf-8)
    ("utf8x" . utf-8))) ; used by the Unicode LaTeX package
  "Mapping from LaTeX encodings in \"inputenc.sty\" to Emacs coding systems.
LaTeX encodings are specified with \"\\usepackage[encoding]{inputenc}\".
Used by the function `latexenc-find-file-coding-system'."
  :group 'files
  :group 'mule
  :type '(alist :key-type (string :tag "LaTeX input encoding")
		:value-type (coding-system :tag "Coding system")))

;;;###autoload
(defun latexenc-inputenc-to-coding-system (inputenc)
  "Return the corresponding coding-system for the specified input encoding.
Return nil if no matching coding system can be found."
  (cdr (assoc inputenc latex-inputenc-coding-alist)))

;;;###autoload
(defun latexenc-coding-system-to-inputenc (cs)
  "Return the corresponding input encoding for the specified coding system.
Return nil if no matching input encoding can be found."
  (let (result)
    (catch 'result
      (dolist (elem latex-inputenc-coding-alist result)
	(let ((elem-cs (cdr elem)))
	  (when (and (coding-system-p elem-cs)
		     (coding-system-p cs)
		     (eq (coding-system-base cs) (coding-system-base elem-cs)))
	    (setq result (car elem))
	    (throw 'result result)))))))

(defvar latexenc-dont-use-TeX-master-flag nil
  "Non-nil means don't follow TeX-master to find the coding system.")

(defvar latexenc-dont-use-tex-guess-main-file-flag nil
  "Non-nil means don't use tex-guessmain-file to find the coding system.")

;;;###autoload
(defun latexenc-find-file-coding-system (arg-list)
  "Determine the coding system of a LaTeX file if it uses \"inputenc.sty\".
The mapping from LaTeX's \"inputenc.sty\" encoding names to Emacs
coding system names is determined from `latex-inputenc-coding-alist'."
  (if (eq (car arg-list) 'insert-file-contents)
      (save-excursion
        ;; try to find the coding system in this file
        (goto-char (point-min))
	(if (catch 'cs
	      (let ((case-fold-search nil))
		(while (search-forward "inputenc" nil t)
		  (goto-char (match-beginning 0))
		  (beginning-of-line)
		  (if (or (looking-at "[^%\n]*\\\\usepackage\\[\\([^]]*\\)\\]{\\([^}]*,\\)?inputenc\\(,[^}]*\\)?}")
			  (looking-at "[^%\n]*\\\\inputencoding{\\([^}]*\\)}"))
		      (throw 'cs t)
		    (goto-char (match-end 0))))))
	    (let* ((match (match-string 1))
		   (sym (or (latexenc-inputenc-to-coding-system match)
                            (intern match))))
	      (cond
               ((coding-system-p sym) sym)
               ((and (require 'code-pages nil t) (coding-system-p sym)) sym)
               (t 'undecided)))
          ;; else try to find it in the master/main file

	  ;; Fixme: If the current file is in an archive (e.g. tar,
	  ;; zip), we should find the master file in that archive.
	  ;; But, that is not yet implemented.   -- K.Handa
          (let ((default-directory (if (stringp (nth 1 arg-list))
				       (file-name-directory (nth 1 arg-list))
				     default-directory))
		latexenc-main-file)
            ;; Is there a TeX-master or tex-main-file in the local variables
            ;; section?
            (unless latexenc-dont-use-TeX-master-flag
              (goto-char (point-max))
	      (search-backward "\n\^L" (max (- (point-max) 3000) (point-min))
                               'move)
	      (search-forward "Local Variables:" nil t)
              (when (re-search-forward
                     "^%+ *\\(TeX-master\\|tex-main-file\\): *\"\\(.+\\)\""
                     nil t)
                (let ((file (match-string 2)))
                  (dolist (ext `("" ,(if (boundp 'TeX-default-extension)
                                         (concat "." TeX-default-extension)
                                       "")
                                 ".tex" ".ltx" ".dtx" ".drv"))
                    (if (and (null latexenc-main-file) ;Stop at first.
                             (file-exists-p (concat file ext)))
                        (setq latexenc-main-file (concat file ext)))))))
            ;; try tex-modes tex-guess-main-file
            (when (and (not latexenc-dont-use-tex-guess-main-file-flag)
                       (not latexenc-main-file))
              ;; Use a separate `when' so the byte-compiler sees the fboundp.
              (when (fboundp 'tex-guess-main-file)
                (let ((tex-start-of-header "\\\\document\\(style\\|class\\)"))
                  (setq latexenc-main-file (tex-guess-main-file)))))
            ;; if we found a master/main file get the coding system from it
            (if (and latexenc-main-file
                     (file-regular-p latexenc-main-file)
                     (file-readable-p latexenc-main-file))
                (let* ((latexenc-dont-use-tex-guess-main-file-flag t)
                       (latexenc-dont-use-TeX-master-flag t)
                       (latexenc-main-buffer
                        (find-file-noselect latexenc-main-file t)))
                  (coding-system-base   ;Disregard the EOL part of the CS.
                   (with-current-buffer latexenc-main-buffer
                     (or coding-system-for-write buffer-file-coding-system
			 'undecided))))
              'undecided))))
    'undecided))


(provide 'latexenc)

;;; latexenc.el ends here