ATTENTION: you probably don't need this plugin! See Why you may not need this plugin.

vim-yapf is a Vim plugin that applies yapf to your current file. yapf automatically formats Python code, based on improved syntax styles.

• yapf

yapf can be installed either with pip:

pip install yapf

or by installing with conda (OSX and linux64 only) with my binstar channel:

conda install -c https://conda.binstar.org/srwalker101 yapf

To format only your changes, use vim-yapf with vim-gitgutter. For example, add following to your vimrc:

call plug#begin('~/.vim/plugged')
" yapf formater
Plug 'dy93/vim-yapf', { 'for': ['python'] }

" gitgutter
Plug 'airblade/vim-gitgutter'
call plug#end()

function! MyAutoFormat()
  let g:gitgutter_async = 0
  execute "GitGutterAll"
  let hunks = GitGutterGetHunks()
  if len(hunks) > 0
    let lines = []
    for hunk in GitGutterGetHunks()
      if hunk[2] <= hunk[2]+hunk[3]-1
        call add(lines, '-l '.hunk[2].'-'.(hunk[2]+hunk[3]-1))
      else
        call add(lines, '-l '.(hunk[2]+hunk[3]-1).'-'.hunk[2])
      endif
    endfor
    echom "Yapf --style ~/.style.yapf ".join(lines, ' ')
    let save = winsaveview()
    execute "Yapf --style ~/.style.yapf ".join(lines, ' ')
    call winrestview(save)
  else
    execute "Yapf --style ~/.style.yapf"
  endif
  let g:gitgutter_async = 1
endfunction

" formater
autocmd BufWritePre *.py :call MyAutoFormat()

and generate your yapf config:

$ yapf --style-help > ~/.style.yapf

Either use a plugin manager and add Plug[in] 'dy93/vim-yapf' to your vimrc, or use pathogen.

The plugin does not create any bindings by default, this is left up to the user. An example could be:

:nnoremap <leader>y :call Yapf()<cr>

or

:nnoremap <leader>y :Yapf<cr>

call function

:Yapf

with arguments

:Yapf --style google

or

:call Yapf(" --style pep8")

The yapf style can be globally set, in your vimrc:

let g:yapf_style = "google"

or

let g:yapf_style = "pep8"

The plugin itself is very simple. It handles user options granted, but at its core it uses ex commands to perform its magic. yapf behaves like a good unix command: it takes text on stdin and spits the altered result to stdout, which is exactly what vim expects.

At its core, this plugin runs the ex command:

0,$!yapf

This pipes the range 0,$ i.e. the whole file through a shell command yapf and replaces the range with the altered result.

Instead of installing this plugin, one could add a mapping e.g.:

autocmd FileType python nnoremap <leader>y :0,$!yapf<Cr><C-o>

Alternatively yapf could be set as the formatprg for the python filetype, and reformatting can be performed with the gq{motion} operator (e.g. with visual selection) to reformat a part of the file. Alternatively alternatively yapf could be set as the equalprg:

setlocal equalprg=yapf

and reformat the whole file with gg=G or a single line with =.