Add hfmt (#33)

rm `stylish-haskell` STDERR redirect to /dev/null

Latest version of `stylish-haskell` supports correct error codes.

Add `hfmt` formatter for Haskell

Update docs

README.md

@@ -194,6 +194,8 @@ endfunction
     [`goimports`](https://godoc.org/golang.org/x/tools/cmd/goimports)
 - Haskell
   - [`stylish-haskell`](https://github.com/jaspervdj/stylish-haskell)
+  - [`hindent`](https://github.com/chrisdone/hindent)
+  - [`hfmt`](https://github.com/danstiner/hfmt)
 - HTML
   - `html-beautify` (ships with [`js-beautify`](https://github.com/beautify-web/js-beautify)),
     [`prettydiff`](https://github.com/prettydiff/prettydiff)

autoload/neoformat/formatters/haskell.vim

@@ -1,5 +1,5 @@
 function! neoformat#formatters#haskell#enabled() abort
-    return ['hindent', 'stylishhaskell']
+    return ['hindent', 'stylishhaskell', 'hfmt']
 endfunction
 
 function! neoformat#formatters#haskell#hindent() abort
@@ -13,7 +13,14 @@ endfunction
 function! neoformat#formatters#haskell#stylishhaskell() abort
     return {
         \ 'exe': 'stylish-haskell',
-        \ 'args': ['2>/dev/null'],
+        \ 'stdin': 1,
+        \ }
+endfunction
+
+function! neoformat#formatters#haskell#hfmt() abort
+    return {
+        \ 'exe': 'hfmt',
+        \ 'args': ['-'],
         \ 'stdin': 1,
         \ }
 endfunction

doc/neoformat.txt

@@ -191,6 +191,8 @@ SUPPORTED FILETYPES				*neoformat-supported-filetypes*
     [`goimports`](https://godoc.org/golang.org/x/tools/cmd/goimports)
 - Haskell
   - [`stylish-haskell`](https://github.com/jaspervdj/stylish-haskell)
+  - [`hindent`](https://github.com/chrisdone/hindent)
+  - [`hfmt`](https://github.com/danstiner/hfmt)
 - HTML
   - `html-beautify` (ships with [`js-beautify`](https://github.com/beautify-web/js-beautify)),
     [`prettydiff`](https://github.com/prettydiff/prettydiff)