4 **General-purpose text-checker interface for Emacs text editor**
10 Wcheck mode is a general-purpose text-checker interface for [Emacs][]
11 text editor. Wcheck mode is a minor mode which provides an on-the-fly
12 text checker. It checks the visible text area, as you type, and possibly
13 highlights some parts of it. What is checked and how are all
16 Wcheck mode can use external programs or Emacs Lisp functions for
17 checking text. For example, Wcheck mode can be used with spell-checker
18 programs such as Ispell, Enchant and Hunspell, but actually any tool
19 that can receive text from standard input stream and send text to
20 standard output can be used. Wcheck mode sends parts of buffer's content
21 to an external program or an Emacs Lisp function and, relying on their
22 output, decides if some parts of text should be marked in the buffer.
24 [Emacs]: http://www.gnu.org/software/emacs/
30 In Wcheck mode's configuration different configuration units are called
31 _languages_. In terms of a spelling checker it is natural to think of
32 them as different human languages. Wcheck mode is not limited to that,
33 though. Language is just a configuration unit for a specific text
36 Each language can use its own checker engine (external program or a
37 function), command-line arguments and other settings, such as the
38 regular expressions and syntax table that are used to match words (or
39 other text elements) in Emacs buffer. User can choose which _face_ is
40 used to mark text elements in buffer.
42 User can create language-specific and major mode specific settings
43 defining which _faces_ to read or skip in buffers. A typical use for
44 this feature is to spell-check only those areas in buffer which are
45 written in the target language. For example, in email messages usually
46 the message body and Subject header are important enough to spell-check.
47 In programming modes user could spell-check only documentation strings
48 and comments (or the opposite if you want to use Wcheck mode to check
49 keywords and syntax of the programming language itself).
51 Wcheck mode can also be configured to offer any kind of actions for
52 marked text. Actions are presented to user through a menu which is
53 activated either by (1) clicking the right mouse button on a marked text
54 or (2) executing interactive command `wcheck-actions` while the cursor
55 (the point) is on a marked text.
57 If you use Wcheck mode as a spelling checker then it's natural to
58 configure an action menu that offers spelling suggestions for misspelled
59 words. The action menu could also have an option to add marked word to
60 spell-checker's dictionary, so that the word is recognized in the
61 future. That's only one application for Wcheck mode, though. Wcheck mode
62 can be configured to find almost any kind of text elements from buffer,
63 mark them, and offer any kind of actions for marked text.
66 How does it compare to other spell-checkers?
67 --------------------------------------------
69 The open design makes Wcheck mode (internally) quite different from
70 spell-checkers like [Flyspell][] mode and [Speck][] mode. They are
71 specific tools for spell-checking through Ispell or compatible program
72 and are therefore very much tied to Ispell's features and command-line
73 interface. This can be useful if you want to use Ispell or fully
74 compatible program for spell-checking natural languages. However, not
75 all human languages can be supported through Ispell and there can also
76 be other kind of text-checking needs.
78 The motivation behind Wcheck mode is to offer more general-purpose and
79 configurable interface for text checking. It can be configured to work
80 with almost anything: user's custom shell, Awk or Perl scripts, Lisp
81 functions or other checkers and text filters. Even if you only need a
82 spelling checker for human languages Wcheck mode can be a good choice.
83 It has more configuration possibilities than other spell-checkers and
84 the on-the-fly checker performs very well. It's a true real-time
87 [Flyspell]: http://www.emacswiki.org/emacs/FlySpell
88 [Speck]: http://www.emacswiki.org/SpeckMode
94 You can install Wcheck mode through [Melpa][] package archive.
95 Alternatively you can put `wcheck-mode.el` file to some directory in
96 your Emacs's `load-path` and add the following lines to Emacs's
97 initialization file (`~/.emacs` or `~/.emacs.d/init.el`):
99 (autoload 'wcheck-mode "wcheck-mode"
100 "Toggle wcheck-mode." t)
101 (autoload 'wcheck-change-language "wcheck-mode"
102 "Switch wcheck-mode languages." t)
103 (autoload 'wcheck-actions "wcheck-mode"
104 "Open actions menu." t)
105 (autoload 'wcheck-jump-forward "wcheck-mode"
106 "Move point forward to next marked text area." t)
107 (autoload 'wcheck-jump-backward "wcheck-mode"
108 "Move point backward to previous marked text area." t)
110 [Melpa]: https://melpa.org/
113 Configuration and basic usage
114 -----------------------------
116 The internal documentation of variable `wcheck-language-data` has a
117 complete description on how to configure Wcheck mode language data. For
118 easy configuration you can use the options in the customize group named
119 _wcheck_ (`M-x customize-group RET wcheck RET`).
121 It might be convenient to bind Wcheck mode commands to some easily
122 accessible keys, for example:
124 (global-set-key (kbd "C-c s") 'wcheck-mode)
125 (global-set-key (kbd "C-c l") 'wcheck-change-language)
126 (global-set-key (kbd "C-c c") 'wcheck-actions)
127 (global-set-key (kbd "C-c n") 'wcheck-jump-forward)
128 (global-set-key (kbd "C-c p") 'wcheck-jump-backward)
130 Interactive command `wcheck-mode` toggles the text-checker minor mode
131 for the current buffer. Command `wcheck-change-language` is used to
132 switch languages and command `wcheck-actions` (or the right mouse
133 button) opens an actions menu for marked text. Commands
134 `wcheck-jump-forward` and `wcheck-jump-backward` jump to next or
135 previous marked text area.
137 A note for Emacs Lisp programmers: Emacs Lisp function
138 `wcheck-marked-text-at` returns information about marked text at a
139 buffer position. Programmers can use it to perform any kind of actions
140 for marked text. Function `wcheck-query-language-data` can be used for
141 querying effective configuration data for any language.
147 Here are some examples on how you can fill the `wcheck-language-data`
148 variable. The value is a list of language configurations:
150 (setq wcheck-language-data
156 Perhaps the most common use for Wcheck mode is to spell-check human
157 languages with Ispell (or compatible) spelling checker. Let's start with
158 examples on how to configure that.
160 The following settings configure two languages which are named "British
161 English" and "Finnish". The former language uses Ispell program as the
162 spell-checker engine. The latter uses Enchant which has an
163 Ispell-compatible command-line interface. Both languages use Wcheck
164 mode's actions feature to offer spelling suggestions for misspelled
165 words. Since both spelling checkers print spelling suggestions in the
166 Ispell format we use built-in function
167 `wcheck-parser-ispell-suggestions` to parse the output and populate the
168 actions (spelling suggestions) menu for user.
171 (program . "/usr/bin/ispell")
172 (args "-l" "-d" "british")
173 (action-program . "/usr/bin/ispell")
174 (action-args "-a" "-d" "british")
175 (action-parser . wcheck-parser-ispell-suggestions))
178 (program . "/usr/bin/enchant")
179 (args "-l" "-d" "fi")
180 (syntax . my-finnish-syntax-table)
181 (action-program . "/usr/bin/enchant")
182 (action-args "-a" "-d" "fi")
183 (action-parser . wcheck-parser-ispell-suggestions))
185 The "Finnish" language above used a special syntax table called
186 `my-finnish-syntax-table`. It could be defined like this:
188 (defvar my-finnish-syntax-table
189 (copy-syntax-table text-mode-syntax-table))
191 (modify-syntax-entry ?- "w" my-finnish-syntax-table)
193 It copies `text-mode-syntax-table` (which Wcheck mode uses by default)
194 and sets the syntactic meaning of the ASCII hyphen character (-) to a
195 word character ("w"). Wcheck mode and its regular expression search will
196 use that syntax table when scanning buffers' content in that language.
198 Below is an example on how to add an "Add to dictionary" feature to the
199 actions menu, among spelling suggestions. First, there's the language
200 configuration. The example below is similar to the "British English"
201 configuration above except that Enchant spell-checker is used and
202 `action-parser` is a custom function (which will be defined later).
205 (program . "/usr/bin/enchant")
206 (args "-l" "-d" "en_GB")
207 (action-program . "/usr/bin/enchant")
208 (action-args "-a" "-d" "en_GB")
209 (action-parser . enchant-suggestions-menu))
211 The action parser is custom function `enchant-suggestions-menu`. It will
212 call `wcheck-parser-ispell-suggestions` and then add "Add to dictionary"
213 option in the front of the spelling suggestions list. Choosing that
214 option from the actions menu will call function
215 `enchant-add-to-dictionary` (will be defined later).
217 (defun enchant-suggestions-menu (marked-text)
218 (cons (cons "[Add to dictionary]" 'enchant-add-to-dictionary)
219 (wcheck-parser-ispell-suggestions)))
221 Now we need to define the function `enchant-add-to-dictionary`. Below is
222 an example that works in GNU/Linux systems with Enchant spell-checker.
223 With small modifications it should work with other spelling checkers and
226 For British English language the user dictionary file is
227 `~/.config/enchant/en_GB.dic`. The language code is extracted
228 automatically from `wcheck-language-data` variable, so the function
229 works with any Enchant language. Note that adding a word to a dictionary
230 file doesn't have effect on the current spell-checking session. The
231 Enchant program must be restarted.
233 (defvar enchant-dictionaries-dir "~/.config/enchant")
235 (defun enchant-add-to-dictionary (marked-text)
236 (let* ((word (aref marked-text 0))
237 (language (aref marked-text 4))
238 (file (let ((code (nth 1 (member "-d" (wcheck-query-language-data
239 language 'action-args)))))
241 (concat (file-name-as-directory enchant-dictionaries-dir)
244 (when (and file (file-writable-p file))
246 (insert word) (newline)
247 (append-to-file (point-min) (point-max) file)
248 (message "Added word \"%s\" to the %s dictionary"
251 Spell-checking human languages is not the only application for Wcheck
252 mode. The following configuration adds language called "Trailing
253 whitespace" which finds and marks all trailing whitespace characters
254 (spaces and tabs) on buffer's lines. It uses regular expressions to
255 match the whitespace. The checker program is the Emacs Lisp function
256 `identity` which just returns its argument unchanged. The
257 `action-program` option and feature is used to build an action menu with
258 just one option: remove the whitespace. It replaces the original
259 whitespace string with empty string.
261 ("Trailing whitespace"
263 (action-program . (lambda (marked-text)
264 (list (cons "Remove whitespace" ""))))
267 (regexp-body . "[ \t]+")
269 (regexp-discard . "")
273 Sometimes it's useful to highlight only a small number of keywords in
274 buffer. The following example adds a language called "Highlight FIXMEs"
275 which marks only "FIXME" words. FIXME is some programmers' convention to
276 put reminders in source code that some parts are not complete yet and
277 will be fixed or completed later. In source code files such keywords are
278 written in program's comments only, not in the actual code, so we use
279 `read-or-skip-faces` feature to scan only the comments. This example
280 configures it for `emacs-lisp-mode` and `c-mode`. In all other major
281 modes FIXMEs are marked everywhere.
284 (program . (lambda (strings)
285 (when (member "FIXME" strings)
289 ((emacs-lisp-mode c-mode) read font-lock-comment-face)
292 The following example adds a language "email" for highlighting email
293 addresses in buffer and creating an action menu which has option to
294 start composing mail to that address. Here's the language configuration:
297 (program . email-address-detect)
300 (regexp-start . "\\<")
301 (regexp-body . "\\S-+@\\S-+")
303 (regexp-discard . "")
304 (action-program . email-action-menu)
308 Then the needed functions:
310 (defun email-address-detect (strings)
312 (dolist (string strings addresses)
313 (when (string-match "\\<[a-z.-]+\\>@\\<[a-z.-]+\\>" string)
314 (push (match-string-no-properties 0 string) addresses)))))
316 (defun email-action-menu (marked-text)
317 (list (cons (concat "Mail to <" (aref marked-text 0) ">")
318 (lambda (marked-text)
319 (compose-mail (aref marked-text 0))))))
321 Note that detecting all valid email addresses is difficult and a much
322 more advanced parser is needed for that. Feel free to replace the
323 detection function with a better one.
326 The source code repository
327 --------------------------
329 GitHub repository URL: <https://github.com/tlikonen/wcheck-mode>
331 The branch named _master_ is the release branch and it should always be
332 safe to use. New features and experimental code are developed in other
333 branches and possibly merged to _master_ when they are ready.
336 Copyright and license
337 ---------------------
339 Copyright (C) 2009-2016 Free Software Foundation, Inc.
341 This program is free software: you can redistribute it and/or modify it
342 under the terms of the GNU General Public License as published by the
343 Free Software Foundation, either version 3 of the License, or (at your
344 option) any later version.
346 This program is distributed in the hope that it will be useful, but
347 WITHOUT ANY WARRANTY; without even the implied warranty of
348 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
349 Public License for more details.
351 The license text: <http://www.gnu.org/licenses/gpl-3.0.html>