Add OCaml support with ocamlformat

README.md

@@ -22,6 +22,7 @@ helpfiles in the `doc/` directory. The helpfiles are also available via
 * Java (google-java-format or clang-format)
 * JavaScript (clang-format or [prettier](https://prettier.io))
 * JSON (js-beautify)
+* [OCaml](https://ocaml.org) ([ocamlformat](https://github.com/ocaml-ppx/ocamlformat))
 * Proto (clang-format)
 * Python (Autopep8, Black, or YAPF)
 * Rust ([rustfmt](https://github.com/rust-lang/rustfmt))

autoload/codefmt.vim

@@ -33,6 +33,7 @@
 "   * fish: fish_indent
 "   * gn: gn
 "   * go: gofmt
+"   * ocaml: ocamlformat
 "   * python: autopep8, black, yapf
 
 

autoload/codefmt/ocamlformat.vim

@@ -0,0 +1,86 @@
+" Copyright 2020 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: ocamlformat
+function! codefmt#ocamlformat#GetFormatter() abort
+  let l:formatter = {
+      \ 'name': 'ocamlformat',
+      \ 'setup_instructions': 'Install ocamlformat' .
+          \ '(https://github.com/ocaml-ppx/ocamlformat)'}
+
+  function l:formatter.IsAvailable() abort
+    return executable(s:plugin.Flag('ocamlformat_executable'))
+  endfunction
+
+  function l:formatter.AppliesToBuffer() abort
+    return &filetype is# 'ocaml'
+  endfunction
+
+  ""
+  " Reformat the current buffer with ocamlformat or the binary named in
+  " @flag(ocamlformat_executable), only targeting the range between {startline} and
+  " {endline}.
+  function l:formatter.FormatRange(startline, endline) abort
+    let l:cmd = [ s:plugin.Flag('ocamlformat_executable'), '-' ]
+    let l:fname = expand('%:p')
+    if !empty(l:fname)
+      let l:cmd += ['--name', l:fname]
+      let l:fname_pattern = '"' . escape(l:fname, '\') . '"'
+    else
+      " assume it's an OCaml implementation file (.ml) if no file name is
+      " provided
+      let l:cmd += ['--impl']
+      let l:fname_pattern = '\<standard input\>'
+    end
+    try
+      " NOTE: ocamlformat does not support range formatting.
+      " See https://github.com/ocaml-ppx/ocamlformat/pull/1188
+      call codefmt#formatterhelpers#AttemptFakeRangeFormatting(
+          \ a:startline, a:endline, l:cmd)
+    catch /ERROR(ShellError):/
+      " Parse all the errors and stick them in the quickfix list.
+      let l:errors = []
+      let l:matchidx = 1
+      while 1
+        let l:tokens = matchlist(v:exception,
+            \ '\vFile ' . l:fname_pattern . ', line (\d+), characters (\d+)-\d+:\n(.*)\n', 0, l:matchidx)
+        if empty(l:tokens)
+          break
+        endif
+        call add(l:errors, {
+            \ 'filename': @%,
+            \ 'lnum': l:tokens[1] + a:startline - 1,
+            \ 'col': l:tokens[2],
+            \ 'text': l:tokens[3]})
+        let l:matchidx = l:matchidx + 1
+      endwhile
+
+      if empty(l:errors)
+        " Couldn't parse ocamlformat error format; display it all.
+        call maktaba#error#Shout('Error formatting file: %s', v:exception)
+      else
+        call setqflist(l:errors, 'r')
+        cc 1
+      endif
+    endtry
+  endfunction
+
+  return l:formatter
+endfunction

doc/codefmt.txt

@@ -54,14 +54,14 @@ Default: 'dartfmt' `
 The path to the js-beautify executable.
 Default: 'js-beautify' `
 
-                                                     *codefmt:black_executable*
-The path to the black executable.
-Default: 'black' `
-
                                                      *codefmt:yapf_executable*
 The path to the yapf executable.
 Default: 'yapf' `
 
+                                                    *codefmt:black_executable*
+The path to the black executable.
+Default: 'black' `
+
                                                        *codefmt:gn_executable*
 The path to the gn executable.
 Default: 'gn' `
@@ -122,6 +122,10 @@ Default: 'zprint' `
 The path to the fish_indent executable.
 Default: 'fish_indent' `
 
+                                              *codefmt:ocamlformat_executable*
+The path to the ocamlformat executable.
+Default: 'ocamlformat' `
+
                                                     *codefmt:plugin[autocmds]*
 Configures whether plugin/autocmds.vim should be loaded.
 Default: 1 `
@@ -168,6 +172,7 @@ The current list of defaults by filetype is:
   * fish: fish_indent
   * gn: gn
   * go: gofmt
+  * ocaml: ocamlformat
   * python: autopep8, black, yapf
 
 ==============================================================================

instant/flags.vim

@@ -168,3 +168,7 @@ call s:plugin.Flag('zprint_executable', 'zprint')
 ""
 " The path to the fish_indent executable.
 call s:plugin.Flag('fish_indent_executable', 'fish_indent')
+
+""
+" The path to the ocamlformat executable.
+call s:plugin.Flag('ocamlformat_executable', 'ocamlformat')

plugin/register.vim

@@ -38,3 +38,4 @@ call s:registry.AddExtension(codefmt#googlejava#GetFormatter())
 call s:registry.AddExtension(codefmt#shfmt#GetFormatter())
 call s:registry.AddExtension(codefmt#zprint#GetFormatter())
 call s:registry.AddExtension(codefmt#fish_indent#GetFormatter())
+call s:registry.AddExtension(codefmt#ocamlformat#GetFormatter())

vroom/ocamlformat.vroom

@@ -0,0 +1,100 @@
+The built-in ocamlformat formatter knows how to format ocaml code.
+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 ocamlformat formatter expects the ocamlformat executable to be installed on your system.
+
+  @clear
+  % f()
+  :FormatCode ocamlformat
+  ! ocamlformat .*
+  $ ;;
+  $ f ()
+  ;;
+  f ()
+  @end
+
+The name or path of the ocamlformat executable can be configured via the
+ocamlformat_executable flag if the default of "ocamlformat" doesn't work.
+
+  @clear
+  :Glaive codefmt ocamlformat_executable='myocamlformat'
+  :FormatCode ocamlformat
+  ! myocamlformat .*
+  $ ;;
+  $ f ()
+  :Glaive codefmt ocamlformat_executable='ocamlformat'
+
+
+You can format any buffer with ocamlformat specifying the formatter explicitly.
+
+  @clear
+  % let x=5 in<CR>
+  |  let inc x=x+1 in<CR>
+  |    print_endline (string_of_int (inc x))
+
+  :FormatCode ocamlformat
+  ! ocamlformat .*
+  $ ;;
+  $ let x = 5 in
+  $ let inc x = x + 1 in
+  $ print_endline (string_of_int (inc x))
+  ;;
+  let x = 5 in
+  let inc x = x + 1 in
+  print_endline (string_of_int (inc x))
+  @end
+
+The ocaml filetype will use the ocamlformat formatter by default. The path to the
+file being edited is passed to ocamlformat so that it can adjust to whether the
+file is an implementation or an interface file.
+
+  @clear
+  % f()
+
+  :silent file /foo/bar/test.ml
+  :set filetype=ocaml
+  :FormatCode
+  ! ocamlformat - --name /foo/bar/test.ml .*
+  $ ;;
+  $ f ()
+  ;;
+  f ()
+  @end
+
+It can format specific line ranges of code using :FormatLines.
+
+  @clear
+  % print_string "Hello";;<CR>
+  |let x=1 in let y=2 in<CR>
+  |y+2
+
+  :2,3FormatLines ocamlformat
+  ! ocamlformat .*
+  $ ;;
+  $ let x = 1 in
+  $ let y = 2 in
+  $ y + 2
+  print_string "Hello";;
+  ;;
+  let x = 1 in
+  let y = 2 in
+  y + 2
+  @end
+
+NOTE: the ocamlformat formatter does not natively support range formatting, so there
+are certain limitations like not being able to format misaligned braces.
+