1 ;;; flow-fill.el --- interpret RFC2646 "flowed" text
3 ;; Copyright (C) 2000, 2001, 2002, 2003, 2004,
4 ;; 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
6 ;; Author: Simon Josefsson <jas@pdc.kth.se>
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software: you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation, either version 3 of the License, or
14 ;; (at your option) any later version.
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
26 ;; This implement decoding of RFC2646 formatted text, including the
27 ;; quoted-depth wins rules.
29 ;; Theory of operation: search for lines ending with SPC, save quote
30 ;; length of line, remove SPC and concatenate line with the following
31 ;; line if quote length of following line matches current line.
33 ;; When no further concatenations are possible, we've found a
34 ;; paragraph and we let `fill-region' fill the long line into several
35 ;; lines with the quote prefix as `fill-prefix'.
37 ;; Todo: implement basic `fill-region' (Emacs and XEmacs
38 ;; implementations differ..)
42 ;; 2000-02-17 posted on ding mailing list
43 ;; 2000-02-19 use `point-at-{b,e}ol' in XEmacs
44 ;; 2000-03-11 no compile warnings for point-at-bol stuff
45 ;; 2000-03-26 committed to gnus cvs
46 ;; 2000-10-23 don't flow "-- " lines, make "quote-depth wins" rule
47 ;; work when first line is at level 0.
48 ;; 2002-01-12 probably incomplete encoding support
49 ;; 2003-12-08 started working on test harness.
53 (eval-when-compile (require 'cl
))
55 (defcustom fill-flowed-display-column
'fill-column
56 "Column beyond which format=flowed lines are wrapped, when displayed.
57 This can be a Lisp expression or an integer."
60 :type
'(choice (const :tag
"Standard `fill-column'" fill-column
)
61 (const :tag
"Fit Window" (- (window-width) 5))
65 (defcustom fill-flowed-encode-column
66
66 "Column beyond which format=flowed lines are wrapped, in outgoing messages.
67 This can be a Lisp expression or an integer.
68 RFC 2646 suggests 66 characters for readability."
71 :type
'(choice (const :tag
"Standard fill-column" fill-column
)
72 (const :tag
"RFC 2646 default (66)" 66)
77 (defun fill-flowed-encode (&optional buffer
)
78 (with-current-buffer (or buffer
(current-buffer))
79 ;; No point in doing this unless hard newlines is used.
80 (when use-hard-newlines
81 (let ((start (point-min)) end
)
82 ;; Go through each paragraph, filling it and adding SPC
83 ;; as the last character on each line.
84 (while (setq end
(text-property-any start
(point-max) 'hard
't
))
85 (let ((fill-column (eval fill-flowed-encode-column
)))
86 (fill-region start end t
'nosqueeze
'to-eop
))
88 ;; `fill-region' probably distorted end.
89 (setq end
(text-property-any start
(point-max) 'hard
't
))
90 (while (and (< (point) end
)
91 (re-search-forward "$" (1- end
) t
))
95 (goto-char (setq start
(1+ end
)))))
99 (defun fill-flowed (&optional buffer delete-space
)
100 (with-current-buffer (or (current-buffer) buffer
)
101 (goto-char (point-min))
102 ;; Remove space stuffing.
103 (while (re-search-forward "^\\( \\|>+ $\\)" nil t
)
106 (goto-char (point-min))
107 (while (re-search-forward " $" nil t
)
110 (when (save-excursion
112 (looking-at "^\\(>*\\)\\( ?\\)"))
113 (let ((quote (match-string 1))
115 (if (string= quote
"")
117 (when (and quote
(string= (match-string 2) ""))
119 ;; insert SP after quote for pleasant reading of quoted lines
121 (when (> (skip-chars-forward ">") 0)
123 ;; XXX slightly buggy handling of "-- "
124 (while (and (save-excursion
125 (ignore-errors (backward-char 3))
126 (setq sig
(looking-at "-- "))
127 (looking-at "[^-][^-] "))
131 (looking-at (format "^\\(%s\\)\\([^>\n\r]\\)"
134 (replace-match (if (string= (match-string 2) " ")
136 (backward-delete-char -
1)
140 (let ((fill-prefix (when quote
(concat quote
" ")))
141 (fill-column (eval fill-flowed-display-column
))
144 (fill-region (point-at-bol)
145 (min (1+ (point-at-eol))
154 (defvar show-trailing-whitespace
)
156 (defvar fill-flowed-encode-tests
158 ;; The syntax of each list element is:
159 ;; (INPUT . EXPECTED-OUTPUT)
161 "> Thou villainous ill-breeding spongy dizzy-eyed \n"
162 "> reeky elf-skinned pigeon-egg! \n"
163 ">> Thou artless swag-bellied milk-livered \n"
164 ">> dismal-dreaming idle-headed scut!\n"
165 ">>> Thou errant folly-fallen spleeny reeling-ripe \n"
166 ">>> unmuzzled ratsbane!\n"
167 ">>>> Henceforth, the coding style is to be strictly \n"
168 ">>>> enforced, including the use of only upper case.\n"
169 ">>>>> I've noticed a lack of adherence to the coding \n"
170 ">>>>> styles, of late.\n"
171 ">>>>>> Any complaints?")
174 "> Thou villainous ill-breeding spongy dizzy-eyed reeky elf-skinned\n"
176 ">> Thou artless swag-bellied milk-livered dismal-dreaming idle-headed\n"
178 ">>> Thou errant folly-fallen spleeny reeling-ripe unmuzzled ratsbane!\n"
179 ">>>> Henceforth, the coding style is to be strictly enforced,\n"
180 ">>>> including the use of only upper case.\n"
181 ">>>>> I've noticed a lack of adherence to the coding styles, of late.\n"
182 ">>>>>> Any complaints?\n"
196 (defun fill-flowed-test ()
198 (switch-to-buffer (get-buffer-create "*Format=Flowed test output*"))
200 (setq show-trailing-whitespace t
)
201 (dolist (test fill-flowed-encode-tests
)
203 (insert "***** BEGIN TEST INPUT *****\n")
205 (insert "***** END TEST INPUT *****\n\n")
206 (insert "***** BEGIN TEST OUTPUT *****\n")
210 (narrow-to-region start
(point))
212 (setq output
(buffer-substring start
(point-max)))
213 (insert "***** END TEST OUTPUT *****\n")
214 (unless (string= output
(cdr test
))
215 (insert "\n***** BEGIN TEST EXPECTED OUTPUT *****\n")
217 (insert "***** END TEST EXPECTED OUTPUT *****\n"))
219 (goto-char (point-max)))
223 ;;; flow-fill.el ends here