yapf_format.py

# This is a copy of the clang-format vim-integration script, refactored to work
# with yapf.
# Questions and/or suggestions? I'm @pignacio in github.
# This script is hosted at http://gist.github.com/pignacio/f93218bbafa2aa94610c
# I'm not sure if this works properly in windows/mac. Only tested in linux.
#
# This file is a minimal yapf vim-integration. To install:
# - Change 'binary' if yapf is not on the path (see below).
# - Add to your .vimrc:
#
#   map <C-I> :%pyf <path-to-this-file>/yapf_format.py<CR>
#   imap <C-I> <ESC>:pyf <path-to-this-file>/yapf_format.py<CR>i
#   vmap <C-I> :pyf <path-to-this-file>/yapf_format.py<CR>
#
# The first line enables yapf_format for NORMAL mode, the second line adds
# support for INSERT mode, and the third for VISUAL.  Change "C-I" to another
# binding if you need yapf_format on a different key (C-I stands for Ctrl+i).
#
# With this integration you can press the bound key and yapf will format the
# whole file in NORMAL mode, the current line in INSERT mode or the selected
# region in VISUAL mode.
#
# It operates on the current, potentially unsaved buffer and does not create
# or save any files. To revert a formatting, just undo.

import difflib
import subprocess
import sys
import vim

# Change this to the full path if yapf is not on the path.
binary = 'yapf'

# Change this to format according to other formatting styles.
style = 'pep8'


def main():
    # Get the current text.
    buf = vim.current.buffer
    text = '\n'.join(buf)

    # Determine range to format.
    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 yapf.
    startupinfo = None
    if sys.platform.startswith('win32'):
        startupinfo = subprocess.STARTUPINFO()
        startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
        startupinfo.wShowWindow = subprocess.SW_HIDE

    # Call formatter.
    command = '{} --lines {} --style "{}"'.format(binary, lines, style)
    with open('/tmp/yapf-calls', 'a') as fout:
        fout.write(str(command) + '\n')
    p = subprocess.Popen(command,
                         stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE,
                         stdin=subprocess.PIPE,
                         startupinfo=startupinfo,
                         shell=True)
    stdout, stderr = p.communicate(input=text)

    # If successful, replace buffer contents.
    if stderr:
        print stderr

    if not stdout:
        print('No output from yapf (crashed?).\n' +
              'Please report to github.com/google/yapf.')
    else:
        lines = stdout.rstrip('\n').split('\n')
        sequence = difflib.SequenceMatcher(None, vim.current.buffer, 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 __name__ == "__main__":
    main()