#+title: jinx.el - Enchanted Spell Checker
#+author: Daniel Mendler
#+language: en
#+export_file_name: jinx.texi
#+texinfo_dir_category: Emacs misc features
#+texinfo_dir_title: Jinx: (jinx).
#+texinfo_dir_desc: Enchanted Spell Checker

#+html: <a href="https://www.gnu.org/software/emacs/"><img alt="GNU Emacs" src="https://github.com/minad/corfu/blob/screenshots/emacs.svg?raw=true"/></a>
#+html: <a href="https://elpa.gnu.org/packages/jinx.html"><img alt="GNU ELPA" src="https://elpa.gnu.org/packages/jinx.svg"/></a>
#+html: <a href="https://elpa.gnu.org/devel/jinx.html"><img alt="GNU-devel ELPA" src="https://elpa.gnu.org/devel/jinx.svg"/></a>
#+html: <a href="https://melpa.org/#/jinx"><img alt="MELPA" src="https://melpa.org/packages/jinx-badge.svg"/></a>
#+html: <a href="https://stable.melpa.org/#/jinx"><img alt="MELPA Stable" src="https://stable.melpa.org/packages/jinx-badge.svg"/></a>

Jinx is a fast just-in-time spell-checker for Emacs. Jinx highlights misspelled
words in the text of the visible portion of the buffer. For efficiency, Jinx
highlights misspellings lazily, recognizes window boundaries and text folding,
if any. For example, when unfolding or scrolling, only the newly visible part of
the text is checked if it has not been checked before. Each misspelling can be
corrected from a list of dictionary words presented as a completion menu.

Installing Jinx is straight-forward and configuring should not need much
intervention. Jinx can be used completely on its own, but can also safely
co-exist with Emacs's built-in spell-checker Ispell.

Jinx's high performance and low resource usage comes from directly calling the
widely-used API of the Enchant library (see [[https://abiword.github.io/enchant/][libenchant]]). Jinx automatically
compiles =jinx-mod.c= and loads the dynamic module at startup. By binding directly
to the native Enchant API, Jinx avoids the slower backend process communication
with Aspell. Enchant is widely used by other text editors and supports [[https://nuspell.github.io/][Nuspell]],
[[http://hunspell.github.io/][Hunspell]], [[http://aspell.net/][Aspell]] and a few language-specific backends.

Jinx supports spell-checking multiple languages in the same buffer. See the
=jinx-languages= variable to customize for multiple languages. Jinx can flexibly
ignore misspellings via faces (=jinx-exclude-faces= and =jinx-include-faces=),
regular expressions (=jinx-exclude-regexps=), and programmable predicates. Jinx
comes preconfigured for the most important Emacs major modes. Modes like Java,
Ruby or Rust are listed in =jinx-camel-modes=. For these modes composite words in
=camelCase= and =PascalCase= are accepted.

#+html: <img src="https://github.com/minad/jinx/blob/screenshots/screenshot.png?raw=true">

* Installation

Jinx can be installed from GNU ELPA or MELPA directly with =package-install=.

Jinx requires =libenchant=. Enchant library is a required dependency for Jinx to
compile its module at install time. If =pkgconf= or =pkg-config= is available when
installing Jinx, Jinx will use it to locate =libenchant=. Depending on your
operating system and Linux distribution you have to install different packages:

- Debian or Ubuntu: =libenchant-2-dev=, =pkgconf=
- Guix: =enchant=, =pkgconf=
- Arch: =enchant=, =pkgconf=
- Gentoo: =enchant=, =pkgconf=
- Void: =enchant2-devel=, =pkgconf=
- Fedora or RHEL: =enchant2-devel=, =pkgconf=
- FreeBSD, OpenBSD: =enchant2=, =pkgconf=
- Mac: =enchant2=, =pkgconf=

* Configuration

Jinx has two modes: the command, =global-jinx-mode= activates globally; and the
command, =jinx-mode=, for activating for specific modes.

#+begin_src emacs-lisp
;; Alternative 1: Enable Jinx globally
(add-hook 'emacs-startup-hook #'global-jinx-mode)

;; Alternative 2: Enable Jinx per mode
(dolist (hook '(text-mode-hook prog-mode-hook conf-mode-hook))
  (add-hook hook #'jinx-mode))
#+end_src

The commands =jinx-correct= and =jinx-languages= are autoloaded. Invoking
=jinx-correct= corrects the misspellings. Binding =jinx-correct= to =M-$= chord takes
over that key from the default assignment to =ispell-word=. Since Jinx is
independent of the Ispell package, =M-$= can be re-used.

#+begin_src emacs-lisp
(keymap-global-set "M-$" #'jinx-correct)
(keymap-global-set "C-M-$" #'jinx-languages)
#+end_src

- =M-$= triggers correction for the misspelled word before point.
- =C-u M-$= triggers correction for the entire buffer.

A sample configuration with the popular =use-package= macro is shown here:

#+begin_src emacs-lisp
(use-package jinx
  :hook (emacs-startup . global-jinx-mode)
  :bind (("M-$" . jinx-correct)
         ("C-M-$" . jinx-languages)))
#+end_src

See also the [[https://github.com/minad/jinx/wiki][Jinx Wiki]] for additional configuration tips. The wiki documents
configurations to save misspellings as global abbreviations and support for
Ispell =LocalWords=.

* Correcting misspellings

After invoking the command =jinx-correct=, suggested corrections are displayed as
a completion menu. You can press the displayed digit keys to quickly select a
suggestion. Furthermore the menu offers options to save the word temporarily for
the current session, in the personal dictionary or in the file-local variables.

Note that you can enter arbitrary input at the correction prompt in order to
make the correction or to store a modified word in the personal dictionary.
For example if you typed =alotriomorpc=, the prompt offers you the option
=@alotriomorpc= which would add this word to your personal dictionary upon
selection. You can then correct the option to =@allotriomorphic= and add it to the
dictionary.

While inside the =jinx-correct= prompt, the keys =M-n= and =M-p= are bound to
=jinx-next= and =jinx-previous= respectively and allow you to move the next and
previous misspelled word.

The completion menu is compatible with all popular completion UIs: Vertico, Mct,
Icomplete, Ivy, Helm and the default completions buffer. In case you use Vertico
I suggest that you tweak the completion display via =vertico-multiform-mode= for
the completion category =jinx=. You can for example use the grid display such that
more suggestions fit on the screen and enable annotations.

#+begin_src emacs-lisp
(add-to-list 'vertico-multiform-categories
             '(jinx grid (vertico-grid-annotate . 20)))
(vertico-multiform-mode 1)
#+end_src

* Navigating between misspellings

As mentioned before, when correcting a word with =jinx-correct=, the movement
commands =jinx-next= and =jinx-previous= are available on the keys =M-n= and =M-p= to
navigate to the next and previous misspelling respectively. The movement
commands work from within the minibuffer during =jinx-correct= and also globally
outside the minibuffer context.

While the commands are not bound globally by default, they are available as =M-n=
and =M-p= if point is placed on top of a misspelled word overlay. If you want you
can add them and other commands to the =jinx-mode-map=, such that they are always
available independent of point placement. If =repeat-mode= from Emacs 28 is
enabled, the movement can be repeated with the keys =n= and =p=.

* Enchant backends and personal dictionaries

Enchant uses different backends for different languages. The backends are
ordered as specified in the personal configuration file
=~/.config/enchant/enchant.ordering= and the system-wide configuration file
=/usr/share/enchant-2/enchant.ordering=. Enchant uses Hunspell as default backend
for most languages. There are a few exceptions. For English Enchant prefers
Aspell and for Finnish and Turkish special backends called Voikko and Zemberek
are used. On non-Linux operating systems Enchant may also integrate with the
spell-checker provided by the operating system.

Depending on the backend the personal dictionary will be taken from different
locations, e.g., =~/.aspell.LANG.pws= or =~/.config/enchant/LANG.dic=. It is
possible to symlink different personal dictionaries such that they are shared by
different spell checkers. See the [[https://abiword.github.io/enchant/src/enchant.html][Enchant manual]] for details.

* Alternative spell-checking packages

There exist multiple alternative spell-checking packages for Emacs, most
famously the builtin ispell.el and flyspell.el packages. The main advantages of
Jinx are its automatic checking of the visible text, its sharp focus on
performance and the ability to easily use multiple dictionaries at once. The
following three alternative packages come closest to the behavior of Jinx.

- [[https://github.com/astoff/jit-spell][jit-spell]]: Jinx UI borrows ideas from Augusto Stoffel's Jit-spell. Jit-spell
  uses the less efficient Ispell process communication instead Jinx's calling
  native API. Since Jit-spell highlights misspellings in the entire buffer and
  does not confine to just the visible text, Jit-spell affected load and latency
  negatively in my tests ([[https://github.com/astoff/jit-spell/issues/9][issue on Github]]).

- [[https://codeberg.org/ideasman42/emacs-spell-fu][spell-fu]]: The idea to check words just in the visible text came from Campbell
  Barton's spell-fu package. Spell-fu is fast but incurs high memory overhead on
  account of its dictionary in a hash table. For languages with compound words
  and inflected word forms, this overhead magnifies ([[https://codeberg.org/ideasman42/emacs-spell-fu/issues/40][issue on Codeberg]]). By
  accessing the Enchant API directly, Jinx avoids any overhead. Jinx also
  benefits from the advanced spell-checker algorithms of Enchant (affixation,
  compound words, etc.).

- flyspell: Flyspell is a built-in package. Flyspell highlights misspellings
  while typing. Only the word under the cursor is spell-checked. Jinx, on the
  other hand, is more effective because it automatically checks for misspellings
  in the entire visible text of the buffer at once. Flyspell can check the
  entire buffer but must be instructed to do so via the command =flyspell-buffer=.

* Contributions

Since this package is part of [[https://elpa.gnu.org/packages/jinx.html][GNU ELPA]] contributions require a copyright
assignment to the FSF.
