yudai / flycheck

Modern on the fly syntax checking for GNU Emacs

Flycheck is a modern on-the-fly syntax checking extension for GNU Emacs 24,
intended as replacement for the older Flymake extension which is part of GNU
Emacs.
It uses various syntax checking and linting tools to check the contents of
buffers, and reports warnings and errors directly in the buffer, or in an
optional error list. The following screenshow shows Flycheck at work in a
Haskell buffer, using GHC and Hlint for syntax checking:
align center
The color theme in this screencast is Solarized Light, with the the
Source Code Pro font.
Features

• Supports over 30 programming and markup languages with more than 60 different syntax checking tools
• Fully automatic, fail-safe, on-the-fly syntax checking in background
• Nice error indication and highlighting
• Optional error list popup
• Many customization options
• A comprehensive manual
• A simple interface to define new syntax checkers
• A “doesn't get in your way” guarantee
• Many 3rd party extensions

Installation

Flycheck needs GNU Emacs 24 on a Unix system, and additionally external syntax checking programs for the languages you use. Flycheck does not officially support Windows, but tries to maintain Windows compatibility and should generally work fine on Windows, too. See Prerequisites and Supported Languages for more information.

Install Flycheck from MELPA or MELPA Stable with:

M-x package-install RET flycheck

In your Cask file:

(source gnu)
(source melpa)

(depends-on "flycheck")

See Package Installation for more information.

Documentation

Documentation is available at http://www.flycheck.org:

• Quick start (tutorial)
• User manual (reference information)

Support & Contribution

• Issue tracker and Waffle Board
• Github
• Contributor Guide

Credits

• Contributors
• Credits

License

Flycheck 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.

Flycheck 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 this program. If not, see http://www.gnu.org/licenses/.

See COPYING for details.

The Flycheck documenation is free documentation: you can copy, distribute and/or modify it under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is available at https://github.com/flycheck/flycheck/blob/master/doc/fdl.txt.

Alternatively, you may copy, distribute and/or modify the Flycheck documentation under the terms of the Creative Commons Attribution-ShareAlike 4.0 International Public License. A copy of the license can be obtained at https://creativecommons.org/licenses/by-sa/4.0/legalcode.

Permission is granted to copy, distribute and/or modify the Flycheck logo in /flycheck.svg under the terms of the Creative Commons Attribution-ShareAlike 4.0 International Public License. A copy of the license can be obtained at https://creativecommons.org/licenses/by-sa/4.0/legalcode.