Emacs spell check using Aspell

The flycheck-aspell and flymake-aspell packages add support for spell checking to Flycheck and Flymake using the GNU Aspell application.

Installation

Thanks to Sam Kleinman and Chris Rayner both flycheck-aspell and flymake-aspell can now be found on MELPA. Install them using your preferred package installation method.

Usage

Both packages will use your ispell settings, in particular ispell-dictionary and ispell-local-dictionary if they are set. This means you can use ispell-change-dictionary to set your preferred language on a per-buffer basis. Here are some recommended base ispell settings.

(setq ispell-dictionary "your_default_dictionary")
(setq ispell-program-name "aspell")
(setq ispell-silently-savep t)

Guides on how to configure both packages can be found in the following separate files:

• README-FLYMAKE.md :: for Flymake users
• README-FLYCHECK.md :: for Flycheck users

General differences to flyspell-mode

Emacs already contains a mode for spell checking called flyspell-mode. It works by spell-checking words as you type, which allows for constant performance with arbitrarily large files, but also comes with a number of disadvantages. In particular, it cannot highlight misspelled words that have not been near the cursor in your current editing session. Accessing a list of all misspelled words is also impossible. Lastly, because flyspell-mode has to run code on every keystroke, it can often cause noticeable input delay and stuttering.

In contrast, flycheck-aspell and flymake-aspell asynchronously run Aspell in the background and extract a list of all misspelled words in the full document. This ensures a list of misspelled words is always available, which can be accessed with e.g. flymake-show-diagnostics-buffer or flycheck-list-errors. However, this also means that spell checking performance will slow down approximately linearly with the number of spelling errors. If your file is particularly large it might take a few seconds for new misspelled words to be highlighted. Note that this should never affect editing experience as no additional code is run on user input.

License

These Emacs packages are distributed under the terms of the GPL-3.0-or-later license, meaning 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.

Copyright notices are included with all individual files of source code.