Add ormolu formatter.

README.md

@@ -19,6 +19,7 @@ helpfiles in the `doc/` directory. The helpfiles are also available via
 * Fish ([fish_indent](https://fishshell.com/docs/current/commands.html#fish_indent))
 * Go (gofmt)
 * [GN](https://www.chromium.org/developers/gn-build-configuration) (gn)
+* Haskell ([ormolu](https://github.com/tweag/ormolu))
 * HTML (js-beautify)
 * Java (google-java-format or clang-format)
 * JavaScript (clang-format or [prettier](https://prettier.io))

autoload/codefmt/ormolu.vim

@@ -0,0 +1,66 @@
+" Copyright 2021 Google Inc. All rights reserved.
+"
+" Licensed under the Apache License, Version 2.0 (the "License");
+" you may not use this file except in compliance with the License.
+" You may obtain a copy of the License at
+"
+"     http://www.apache.org/licenses/LICENSE-2.0
+"
+" Unless required by applicable law or agreed to in writing, software
+" distributed under the License is distributed on an "AS IS" BASIS,
+" WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+" See the License for the specific language governing permissions and
+" limitations under the License.
+
+
+let s:plugin = maktaba#plugin#Get('codefmt')
+
+
+""
+" @private
+" Formatter: ormolu
+function! codefmt#ormolu#GetFormatter() abort
+  let l:formatter = {
+      \ 'name': 'ormolu',
+      \ 'setup_instructions': 'Install ormolu ' .
+          \ '(https://hackage.haskell.org/package/ormolu).'}
+
+  function l:formatter.IsAvailable() abort
+    return executable(s:plugin.Flag('ormolu_executable'))
+  endfunction
+
+  function l:formatter.AppliesToBuffer() abort
+    return &filetype is# 'haskell'
+  endfunction
+
+  ""
+  " Reformat the current buffer with ormolu or the binary named in
+  " @flag(ormolu_executable), only targeting the range between {startline} and
+  " {endline}.
+  " @throws ShellError
+  function l:formatter.FormatRange(startline, endline) abort
+    let l:cmd = [s:plugin.Flag('ormolu_executable')]
+
+    let l:lines = getline(1, line('$'))
+    let l:input = join(l:lines, "\n")
+
+    call maktaba#ensure#IsNumber(a:startline)
+    call maktaba#ensure#IsNumber(a:endline)
+
+    if a:startline > 1
+      call extend(l:cmd, ['--start-line', string(a:startline)])
+    endif
+    call extend(l:cmd, ['--end-line', string(a:endline)])
+
+    try
+      let l:syscall = maktaba#syscall#Create(l:cmd).WithStdin(l:input)
+      let l:result = l:syscall.Call()
+      let l:formatted = split(l:result.stdout, "\n")
+      call maktaba#buffer#Overwrite(1, line('$'), l:formatted)
+    catch /ERROR(ShellError):/
+      call maktaba#error#Shout('Error formatting file: %s', v:exception)
+    endtry
+  endfunction
+
+  return l:formatter
+endfunction

instant/flags.vim

@@ -227,3 +227,7 @@ call s:plugin.Flag('luaformatterfiveone_executable', 'luaformatterfiveone')
 ""
 " The path to the cljstyle executable.
 call s:plugin.Flag('cljstyle_executable', 'cljstyle')
+
+""
+" The path to the ormolu executable.
+call s:plugin.Flag('ormolu_executable', 'ormolu')

plugin/register.vim

@@ -33,6 +33,7 @@
 "   * fish: fish_indent
 "   * gn: gn
 "   * go: gofmt
+"   * haskell: ormolu
 "   * java: google-java-format
 "   * javascript, json, html, css: js-beautify
 "   * javascript, html, css, markdown: prettier
@@ -77,3 +78,4 @@ call s:registry.AddExtension(codefmt#yapf#GetFormatter())
 call s:registry.AddExtension(codefmt#rustfmt#GetFormatter())
 call s:registry.AddExtension(codefmt#shfmt#GetFormatter())
 call s:registry.AddExtension(codefmt#swiftformat#GetFormatter())
+call s:registry.AddExtension(codefmt#ormolu#GetFormatter())

vroom/ormolu.vroom

@@ -0,0 +1,131 @@
+The ormolu formatter knows how to format Haskell.
+If you aren't familiar with basic codefmt usage yet, see main.vroom first.
+
+We'll set up codefmt and configure the vroom environment, then jump into some
+examples.
+
+  :source $VROOMDIR/setupvroom.vim
+
+  :let g:repeat_calls = []
+  :function FakeRepeat(...)<CR>
+  |  call add(g:repeat_calls, a:000)<CR>
+  :endfunction
+  :call maktaba#test#Override('repeat#set', 'FakeRepeat')
+
+  :call codefmt#SetWhetherToPerformIsAvailableChecksForTesting(0)
+
+
+The ormolu formatter expects the ormolu executable to be installed
+on your system.
+
+  % f()
+  :FormatCode ormolu
+  ! ormolu .*
+  $ f()
+
+The name or path of the ormolu executable can be configured via the
+ormolu_executable flag if the default of "ormolu" doesn't work.
+
+  :Glaive codefmt ormolu_executable='myormolu'
+  :FormatCode ormolu
+  ! myormolu .*
+  $ f()
+  :Glaive codefmt ormolu_executable='ormolu'
+
+You can format any buffer with ormolu specifying the formatter explicitly.
+
+  @clear
+  % module Main<CR>
+  |<CR>
+  |  where<CR>
+  |<CR>
+  |main:: IO ()<CR>
+  |<CR>
+  |<CR>
+  |{- this is just a comment -}<CR>
+  |main =pure ()<CR>
+  |<CR>
+  |foo :: Int<CR>
+  |foo =<CR>
+  |  5<CR>
+  |  + 5<CR>
+  |<CR>
+  |bar :: Int<CR>
+  |      bar = 7
+
+  :FormatCode ormolu
+  ! ormolu .*2>.*
+  $ module Main where
+  $ 
+  $ main :: IO ()
+  $ {- this is just a comment -}
+  $ main = pure ()
+  $ 
+  $ foo :: Int
+  $ foo =
+  $   5
+  $     + 5
+  $ 
+  $ bar :: Int
+  $ bar = 7
+  module Main where
+
+  main :: IO ()
+  {- this is just a comment -}
+  main = pure ()
+
+  foo :: Int
+  foo =
+    5
+      + 5
+
+  bar :: Int
+  bar = 7
+  @end
+
+It can format specific line ranges of code using :FormatLines.
+
+  @clear
+  % module Main (main) where<CR>
+  |<CR>
+  |main :: IO ()<CR>
+  |{- this is just a comment -}<CR>
+  |main = pure ()<CR>
+  |<CR>
+  |foo :: Int<CR>
+  |foo =<CR>
+  |  5<CR>
+  |      + 5<CR>
+  |<CR>
+  |bar :: Int<CR>
+  |      bar = 7
+
+  :1,5FormatLines ormolu
+  ! ormolu .*2>.*
+  $ module Main (main) where
+  $ 
+  $ main :: IO ()
+  $ {- this is just a comment -}
+  $ main = pure ()
+  $ 
+  $ foo :: Int
+  $ foo =
+  $   5
+  $       + 5
+  $ 
+  $ bar :: Int
+  $       bar = 7
+  module Main (main) where
+
+  main :: IO ()
+  {- this is just a comment -}
+  main = pure ()
+
+  foo :: Int
+  foo =
+    5
+        + 5
+
+  bar :: Int
+        bar = 7
+  @end