Awesome

Accio

Accio asynchronously summons build/compiler/linter output to your screen by wrapping the :compiler and :make commands using both Neovim's and Vim 8's job control API. Output from these programs is displayed in the following ways:

Populating the quickfix list
Placing signs on the error lines
Echoing the error message when the cursor is on an error line.

Note: Vim 8's job API appears to still be unstable at the time of this writing and causes occasional seg faults. I've increased the update interval to try and account for it but use with caution and try not to issue too many Accio commands in a short span of time.

Usage

Accio doesn't provide any pre-configured compilers/syntax checkers, instead it utilizes compiler plugins to run whatever build/compiler/linter programs they specify and parse their output. Vim ships with several compiler plugins but writing your own is fairly straightforward (:h write-compiler-plugin).

To run a single compiler plugin just pass its name to Accio:

i.e. :Accio javac

To run multiple compiler plugins at once and aggregate their results into one quickfix list, pass a list of compiler names to Accio:

i.e. :Accio ["javac", "checkstyle"]
Note: the compiler names must be quoted, otherwise Vim will attempt to resolve them as variable names and throw an error

Adding support for a new compiler is as simple as writing a compiler plugin for it and storing it under $HOME/.vim/compiler/ or $HOME/vimfiles/compiler for Windows.

Accio is not limited to compiler plugins designed to analyze a single file. It can run any compiler plugin, even ones that kick off a project build script. Accio should be able to handle it and load the results into the quickfix list asynchronously.

Javac Example

Vim ships with a javac compiler, but it provides no way to specify the classpath javac should use, instead it relies on the $CLASSPATH environment variable being set up correctly. Unfortunately, this scheme doesn't work well if you're working on multiple Java projects where each project has its own classpath.

One solution is to use a compiler plugin to help determine the classpath for each individual buffer. Below is an example javac compiler plugin for determining the classpath in a maven project with Git as the VCS and using Fugitive to locate the project root folder:

let current_compiler = "IntelliJ"

function! s:get_classpath()
    let project_git_dir = fugitive#extract_git_dir(expand("%:p"))
    let project_root = fnamemodify(project_git_dir, ":h")
    let classpath_cmd = printf("cd %s && mvn dependency:build-classpath", shellescape(project_root))
    let classpath_pattern = 'classpath:\n\zs[^[].\{-\}\ze\n'
    let maven_output = system(classpath_cmd)
    let maven_classes = project_root . "/target/classes:"
    let classpath = maven_classes . matchstr(maven_output, classpath_pattern)
    return classpath
endfunction

if !exists("b:loaded_javac_classpath")
    let b:loaded_javac_classpath = s:get_classpath()
endif

if exists(":CompilerSet") != 2		" older Vim always used :setlocal
  command -nargs=* CompilerSet setlocal <args>
endif

let $CLASSPATH=b:loaded_javac_classpath
CompilerSet makeprg=javac\ %
CompilerSet errorformat=%E%f:%l:\ %m,%-Z%p^,%-C%.%#,%-G%.%#

Save this script to $HOME/.vim/compiler/IntelliJ.vim and it can be run through Accio with the command :Accio IntelliJ.

Configuration and Features

<Plug>AccioPrevWarning and <Plug>AccioNextWarning
- Mappings to jump to the previous/next error line.
- By default these are mapped to [w and ]w (mnemonic: warning).
accio#statusline()
- Statusline function that will report the number of errors in the current buffer.
- Example usage: set statusline+=%#WarningMsg#%{accio#statusline()}%*
g:accio_auto_copen
- Set to 1 to automatically open the quickfix list when the Accio command is invoked, 0 otherwise.

Differences from Neomake

Accio is borne out of my irrational hatred of pre-configured makers and it is intended to be a lightweight alternative to Neomake. My hope for Accio is to feel like it gives more control/flexibility over your compilers/linters.

The other main difference between the two plugins is that Neomake uses both the quickfix list and location list depending on which version of the command you run. Accio will only use the quickfix list for all possible invocations.

I've put a lot of thought into it and come to the conclusion that the transience of location lists are not a good fit for asynchronous operation or error reporting.
I would still entertain arguments in favor of the location list, just open up an issue about it.
For anyone worried about Accio trashing their quickfix list, Accio makes an effort to reuse the quickfix list wherever possible.

Installation

Pathogen
- cd ~/.vim/bundle && git clone https://github.com/pgdouyon/vim-accio.git
Vim-Plug
- Plug 'pgdouyon/vim-accio'
Manual Install
- Copy all the files into the appropriate directory under ~/.vim on *nix or $HOME/vimfiles on Windows