new_contents: # This file is a minimal clang-format vim-integration. To install:
  # - Change 'binary' if clang-format is not on the path (see below).
  # - Add to your .vimrc:
  #
  #   map <C-I> :pyf <path-to-this-file>/clang-format.py<cr>
  #   imap <C-I> <c-o>:pyf <path-to-this-file>/clang-format.py<cr>
  #
  # The first line enables clang-format for NORMAL and VISUAL mode, the second
  # line adds support for INSERT mode. Change "C-I" to another binding if you
  # need clang-format on a different key (C-I stands for Ctrl+i).
  #
  # With this integration you can press the bound key and clang-format will
  # format the current line in NORMAL and INSERT mode or the selected region in
  # VISUAL mode. The line or region is extended to the next bigger syntactic
  # entity.
  #
  # You can also pass in the variable "l:lines" to choose the range for
  # formatting. This variable can either contain "<start line>:<end line>" or
  # "all" to format the full file. So, to format the full file, write a function
  # like:
  # :function FormatFile()
  # :  let l:lines="all"
  # :  pyf <path-to-this-file>/clang-format.py
  # :endfunction
  #
  # It operates on the current, potentially unsaved buffer and does not create
  # or save any files. To revert a formatting, just undo.
  from __future__ import print_function
  
  import difflib
  import json
  import platform
  import subprocess
  import sys
  import vim
  
  # set g:clang_format_path to the path to clang-format if it is not on the path
  # Change this to the full path if clang-format is not on the path.
  binary = 'clang-format'
  if vim.eval('exists("g:clang_format_path")') == "1":
    binary = vim.eval('g:clang_format_path')
  
  # Change this to format according to other formatting styles. See the output of
  # 'clang-format --help' for a list of supported styles. The default looks for
  # a '.clang-format' or '_clang-format' file to indicate the style that should be
  # used.
  style = 'file'
  fallback_style = None
  if vim.eval('exists("g:clang_format_fallback_style")') == "1":
    fallback_style = vim.eval('g:clang_format_fallback_style')
  
  def get_buffer(encoding):
    if platform.python_version_tuple()[0] == '3':
      return vim.current.buffer
    return [ line.decode(encoding) for line in vim.current.buffer ]
  
  def main():
    # Get the current text.
    encoding = vim.eval("&encoding")
    buf = get_buffer(encoding)
    text = '\n'.join(buf)
  
    # Determine range to format.
    if vim.eval('exists("l:lines")') == '1':
      lines = ['-lines', vim.eval('l:lines')]
    elif vim.eval('exists("l:formatdiff")') == '1':
      with open(vim.current.buffer.name, 'r') as f:
        ondisk = f.read().splitlines();
      sequence = difflib.SequenceMatcher(None, ondisk, vim.current.buffer)
      lines = []
      for op in reversed(sequence.get_opcodes()):
        if op[0] not in ['equal', 'delete']:
          lines += ['-lines', '%s:%s' % (op[3] + 1, op[4])]
      if lines == []:
        return
    else:
      lines = ['-lines', '%s:%s' % (vim.current.range.start + 1,
                                    vim.current.range.end + 1)]
  
    # Determine the cursor position.
    cursor = int(vim.eval('line2byte(line("."))+col(".")')) - 2
    if cursor < 0:
      print('Couldn\'t determine cursor position. Is your file empty?')
      return
  
    # Avoid flashing an ugly, ugly cmd prompt on Windows when invoking clang-format.
    startupinfo = None
    if sys.platform.startswith('win32'):
      startupinfo = subprocess.STARTUPINFO()
      startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
      startupinfo.wShowWindow = subprocess.SW_HIDE
  
    # Call formatter.
    command = [binary, '-style', style, '-cursor', str(cursor)]
    if lines != 'all':
      command += lines
    if fallback_style:
      command.extend(['-fallback-style', fallback_style])
    if vim.current.buffer.name:
      command.extend(['-assume-filename', vim.current.buffer.name])
    p = subprocess.Popen(command,
                         stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                         stdin=subprocess.PIPE, startupinfo=startupinfo)
    stdout, stderr = p.communicate(input=text.encode(encoding))
  
    # If successful, replace buffer contents.
    if stderr:
      print(stderr)
  
    if not stdout:
      print(
          'No output from clang-format (crashed?).\n'
          'Please report to bugs.llvm.org.'
      )
    else:
      lines = stdout.decode(encoding).split('\n')
      output = json.loads(lines[0])
      lines = lines[1:]
      sequence = difflib.SequenceMatcher(None, buf, lines)
      for op in reversed(sequence.get_opcodes()):
        if op[0] is not 'equal':
          vim.current.buffer[op[1]:op[2]] = lines[op[3]:op[4]]
      if output.get('IncompleteFormat'):
        print('clang-format: incomplete (syntax errors)')
      vim.command('goto %d' % (output['Cursor'] + 1))
  
  main()
  
subject: add file