Vim: How to indent to an open paren or bracket when hitting enter?

Question

I\'ve been programming Python with Vim for a while but one thing I haven\'t been able to figure out how to do it set it to auto indent to the level of the last open paren.

Answer 1

It has been included in Vim since V7.0 at least:

See the following snippet from usr/share/vim/vim80/indent/python.vim (line 74) https://github.com/vim/vim/blob/master/runtime/indent/python.vim

function GetPythonIndent(lnum)
  ...
  " When inside parenthesis: If at the first line below the parenthesis add
  " two 'shiftwidth', otherwise same as previous line.
  " i = (a
  "       + b
  "       + c)
  call cursor(a:lnum, 1)
  let p = searchpair('(\|{\|\[', '', ')\|}\|\]', 'bW',
      \ "line('.') < " . (a:lnum - s:maxoff) . " ? dummy :"
      \ . " synIDattr(synID(line('.'), col('.'), 1), 'name')"
      \ . " =~ '\\(Comment\\|Todo\\|String\\)$'")
  if p > 0
    if p == plnum
      " When the start is inside parenthesis, only indent one 'shiftwidth'.
      let pp = searchpair('(\|{\|\[', '', ')\|}\|\]', 'bW',
      \ "line('.') < " . (a:lnum - s:maxoff) . " ? dummy :"
      \ . " synIDattr(synID(line('.'), col('.'), 1), 'name')"
      \ . " =~ '\\(Comment\\|Todo\\|String\\)$'")
      if pp > 0
    return indent(plnum) + (exists("g:pyindent_nested_paren") ? eval(g:pyindent_nested_paren) : shiftwidth())
      endif
      return indent(plnum) + (exists("g:pyindent_open_paren") ? eval(g:pyindent_open_paren) : (shiftwidth() * 2))
    endif
    if plnumstart == p
      return indent(plnum)
    endif
    return plindent
  endif
  ...