ALE - Asynchronous Lint Engine

ALE (Asynchronous Lint Engine) is a plugin for providing linting in NeoVim and Vim 8 while you edit your text files.

ALE makes use of NeoVim and Vim 8 job control functions and timers to run linters on the contents of text buffers and return errors as text is changed in Vim. This allows for displaying warnings and errors in files being edited in Vim before files have been saved back to a filesystem.

In other words, this plugin allows you to lint while you type.

NOTE: This Vim plugin has been written pretty quickly so far, and is still in rapid development. Documentation and stable APIs will follow later.

Supported Languages and Tools

This plugin supports the following languages and tools. All available tools will be run in combination, so they can be complementary.

Language	Tools
Bash	-n flag
Bourne Shell	-n flag
C	gcc
CoffeeScript	coffeelint
D	dmd^
Fortran	gcc
Haskell	ghc^
JavaScript	eslint, jscs, jshint
Python	flake8
Ruby	rubocop

^ Supported only on Unix machines via a wrapper script.

If you would like to see support for more languages and tools, please create an issue or create a pull request. If your tool can read from stdin or you have code to suggest which is good, support can be happily added for more tools.

Usage

Once this plugin is installed, while editing your files in supported languages and tools which have been correctly installed, this plugin will send the contents of your text buffers to a variety of programs for checking the syntax and semantics of your programs. By default, linters will be re-run in the background to check your syntax when you open new buffers or as you make edits to your files.

This plugin offers a variety of global flags for turning options on or off, all of which are given defaults and described in the flags file. Linting on open, setting of signs, populating the loclist, and so forth may all be configured as desired.

Selecting Particular Linters

By default, all available tools for all supported languages will be run. If you want to only select a subset of the tools, simply create a g:ale_linters dictionary in your vimrc file mapping filetypes to lists of linters to run.

let g:ale_linters = {
\   'javascript': ['eslint'],
\}

For all languages unspecified in the dictionary, all possible linters will be run for those languages, just as when the dictionary is not defined. Running many linters should not typically obstruct editing in Vim, as they will all be executed in separate processes simultaneously.

This plugin will look for linters in the ale_linters directory. Each directory within corresponds to a particular filetype in Vim, and each file in each directory corresponds to the name of a particular linter.

Always showing gutter

You can keep the sign gutter open at all times by setting the g:ale_sign_column_always to 1

let g:ale_sign_column_always = 1

Customize signs

Use these options to specify what text should be used for signs:

let g:ale_sign_error = '>>'
let g:ale_sign_warning = '--'

Installation

To install this plugin, you should use one of the following methods. For Windows users, replace usage of the Unix ~/.vim directory with %USERPROFILE%\_vim, or another directory if you have configured Vim differently. On Windows, your ~/.vimrc file will be similarly stored in %USERPROFILE%\_vimrc.

Installation with Pathogen

To install this module with Pathogen, you should clone this repository to your bundle directory, and ensure you have the line execute pathogen#infect() in your ~/.vimrc file. You can run the following commands in your terminal to do so:

cd ~/.vim/bundle
git clone https://github.com/w0rp/ale.git

Installation with Vundle

You can install this plugin using Vundle by using the path on GitHub for this repository.

Plugin 'w0rp/ale'

See the Vundle documentation for more information.

Manual Installation

For installation without a package manager, you can clone this git repository into a bundle directory as with pathogen, and add the repository to your runtime path yourself. First clone the repository.

cd ~/.vim/bundle
git clone https://github.com/w0rp/ale.git

Then, modify your ~/.vimrc file to add this plugin to your runtime path.

set nocompatible
filetype off

let &runtimepath.=',~/.vim/bundle/ale'

filetype plugin on

Because the author of this plugin is a weird nerd, this is his preferred installation method.