Support C# linting with mono compiler mcs. (#250)

* Support netcore project linting.

* Support check on the fly.

* Remove debug.

* Rename csc.vim to mcs.vim as it should be.

* Update README.

* Update doc.

* Using `=~#` instead of `=~`.

3 files changed, 42 insertions, 0 deletions

diff --git a/README.md b/README.md
index 200cc5d9..4a7e472c 100644
--- a/README.md
+++ b/README.md
@@ -53,6 +53,7 @@ name. That seems to be the fairest way to arrange this table.
 | Bourne Shell | [-n flag](http://linux.die.net/man/1/sh), [shellcheck](https://www.shellcheck.net/) |
 | C | [cppcheck](http://cppcheck.sourceforge.net), [gcc](https://gcc.gnu.org/), [clang](http://clang.llvm.org/)|
 | C++ (filetype cpp) | [cppcheck] (http://cppcheck.sourceforge.net), [gcc](https://gcc.gnu.org/)|
+| C# | [mcs](http://www.mono-project.com/docs/about-mono/languages/csharp/) |
 | Chef | [foodcritic](http://www.foodcritic.io/) |
 | CoffeeScript | [coffee](http://coffeescript.org/), [coffeelint](https://www.npmjs.com/package/coffeelint) |
 | CSS | [csslint](http://csslint.net/), [stylelint](https://github.com/stylelint/stylelint) |
diff --git a/ale_linters/cs/mcs.vim b/ale_linters/cs/mcs.vim
new file mode 100644
index 00000000..edf3bd27
--- /dev/null
+++ b/ale_linters/cs/mcs.vim
@@ -0,0 +1,40 @@
+if !exists('g:ale_cs_mcs_options')
+    let g:ale_cs_mcs_options = ''
+endif
+
+function! ale_linters#cs#mcs#Handle(buffer, lines) abort
+    " Look for lines like the following.
+    "
+    " Tests.cs(12,29): error CSXXXX: ; expected
+    let l:pattern = '^.\+.cs(\(\d\+\),\(\d\+\)): \(.\+\): \(.\+\)'
+    let l:output = []
+
+    for l:line in a:lines
+        let l:match = matchlist(l:line, l:pattern)
+
+        if len(l:match) == 0
+            continue
+        endif
+
+        call add(l:output, {
+        \   'bufnr': a:buffer,
+        \   'lnum': l:match[1] + 0,
+        \   'vcol': 0,
+        \   'col': l:match[2] + 0,
+        \   'text': l:match[3] . ': ' . l:match[4],
+        \   'type': l:match[3] =~# '^error' ? 'E' : 'W',
+        \   'nr': -1,
+        \})
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('cs',{
+\ 'name': 'mcs',
+\ 'output_stream': 'stderr',
+\ 'executable': 'mcs',
+\ 'command': g:ale#util#stdin_wrapper . ' .cs mcs -unsafe --parse' . g:ale_cs_mcs_options,
+\ 'callback': 'ale_linters#cs#mcs#Handle',
+\ })
+
diff --git a/doc/ale.txt b/doc/ale.txt
index f0c5b162..bda86b63 100644
--- a/doc/ale.txt
+++ b/doc/ale.txt
@@ -68,6 +68,7 @@ The following languages and tools are supported.
 * Bourne Shell: 'shell' (-n flag), 'shellcheck'
 * C: 'cppcheck', 'gcc', 'clang'
 * C++ (filetype cpp): 'cppcheck', 'gcc'
+* C#: 'mcs'
 * Chef: 'foodcritic'
 * CoffeeScript: 'coffee', 'coffelint'
 * CSS: 'csslint', 'stylelint'