Add support for shellcheck linting.

README.md

@@ -29,7 +29,7 @@ name. That seems to be the fairest way to arrange this table.
 | Language | Tools |
 | -------- | ----- |
 | Bash | [-n flag](https://www.gnu.org/software/bash/manual/bash.html#index-set) |
-| Bourne Shell | [-n flag](http://linux.die.net/man/1/sh) |
+| Bourne Shell | [-n flag](http://linux.die.net/man/1/sh), [shellcheck](https://www.shellcheck.net/) |
 | C | [gcc](https://gcc.gnu.org/) |
 | CoffeeScript | [coffeelint](https://www.npmjs.com/package/coffeelint) |
 | D | [dmd](https://dlang.org/dmd-linux.html)^ |

ale_linters/c/gcc.vim

@@ -9,35 +9,6 @@ if !exists('g:ale_c_gcc_options')
     let g:ale_c_gcc_options = '-Wall'
 endif
 
-function! ale_linters#c#gcc#Handle(buffer, lines)
-    " Look for lines like the following.
-    "
-    " <stdin>:8:5: warning: conversion lacks type at end of format [-Wformat=]
-    " <stdin>:10:27: error: invalid operands to binary - (have ‘int’ and ‘char *’)
-    let pattern = '^<stdin>:\(\d\+\):\(\d\+\): \(warning\|error\): \(.\+\)$'
-    let output = []
-
-    for line in a:lines
-        let l:match = matchlist(line, pattern)
-
-        if len(l:match) == 0
-            continue
-        endif
-
-        call add(output, {
-        \   'bufnr': a:buffer,
-        \   'lnum': l:match[1] + 0,
-        \   'vcol': 0,
-        \   'col': l:match[2] + 0,
-        \   'text': l:match[4],
-        \   'type': l:match[3] ==# 'warning' ? 'W' : 'E',
-        \   'nr': -1,
-        \})
-    endfor
-
-    return output
-endfunction
-
 call ALEAddLinter('c', {
 \   'name': 'gcc',
 \   'output_stream': 'stderr',
@@ -45,5 +16,5 @@ call ALEAddLinter('c', {
 \   'command': 'gcc -S -x c -fsyntax-only '
 \       . g:ale_c_gcc_options
 \       . ' -',
-\   'callback': 'ale_linters#c#gcc#Handle',
+\   'callback': 'ale#handlers#HandleGCCFormat',
 \})

ale_linters/sh/shellcheck.vim

@@ -0,0 +1,32 @@
+" Author: w0rp <devw0rp@gmail.com>
+" Description: This file adds support for using the shellcheck linter with
+"   shell scripts.
+
+if exists('g:loaded_ale_linters_sh_shellcheck')
+    finish
+endif
+
+let g:loaded_ale_linters_sh_shellcheck = 1
+
+" This global variable can be set with a string of comma-seperated error
+" codes to exclude from shellcheck. For example:
+"
+" let g:ale_linters_sh_shellcheck_exclusions = 'SC2002,SC2004'
+if !exists('g:ale_linters_sh_shellcheck_exclusions')
+    let g:ale_linters_sh_shellcheck_exclusions = ''
+endif
+
+if g:ale_linters_sh_shellcheck_exclusions != ''
+    let s:exclude_option = '-e ' .  g:ale_linters_sh_shellcheck_exclusions
+else
+    let s:exclude_option = ''
+endif
+
+call ALEAddLinter('sh', {
+\   'name': 'shellcheck',
+\   'executable': 'shellcheck',
+\   'command': 'shellcheck ' . s:exclude_option . ' -f gcc -',
+\   'callback': 'ale#handlers#HandleGCCFormat',
+\})
+
+echo 'shellcheck' . s:exclude_option . '-f gcc -'

plugin/ale/handlers.vim

@@ -0,0 +1,40 @@
+" Author: w0rp <devw0rp@gmail.com>
+" Description: This file defines some standard error format handlers. Any
+"   linter which outputs warnings and errors in a format accepted by one of
+"   these functions can simply use one of these pre-defined error handlers.
+
+if exists('g:loaded_ale_handlers')
+    finish
+endif
+
+let g:loaded_ale_handlers = 1
+
+function! ale#handlers#HandleGCCFormat(buffer, lines)
+    " Look for lines like the following.
+    "
+    " <stdin>:8:5: warning: conversion lacks type at end of format [-Wformat=]
+    " <stdin>:10:27: error: invalid operands to binary - (have ‘int’ and ‘char *’)
+    " -:189:7: note: $/${} is unnecessary on arithmetic variables. [SC2004]
+    let pattern = '^[^:]\+:\(\d\+\):\(\d\+\): \([^:]\+\): \(.\+\)$'
+    let output = []
+
+    for line in a:lines
+        let l:match = matchlist(line, pattern)
+
+        if len(l:match) == 0
+            continue
+        endif
+
+        call add(output, {
+        \   'bufnr': a:buffer,
+        \   'lnum': l:match[1] + 0,
+        \   'vcol': 0,
+        \   'col': l:match[2] + 0,
+        \   'text': l:match[4],
+        \   'type': l:match[3] ==# 'error' ? 'E' : 'W',
+        \   'nr': -1,
+        \})
+    endfor
+
+    return output
+endfunction