Question

Is there any easy way to toggle “do/end” and “{}” in ruby in Vim?

(TextMate does this with ^{.)

Answer 1

You’d have to either use searchpair(), or to play with % (as long as matchit is installed, and as you are on begin/end), then mark the two positions, test whether it’s text or brackets, and finally update the two lines.

nnoremap <buffer> <c-x>{ :call <sid>ToggleBeginOrBracket()<cr>

let s:k_be = [ 'begin', 'end' ]
function! s:ToggleBeginOrBracket()
  let c = lh#position#char_at_mark('.')
  if c =~ '[{}]'
    " don't use matchit for {,}
    exe 'normal! %s'.s:k_be[1-(c=='}')]."\<esc>``s".s:k_be[(c=='}')]."\<esc>"
  else
    let w = expand('<cword>')
    if w == 'begin'
      " use mathit
      normal %
      exe "normal! ciw}\<esc>``ciw{\<esc>"
    elseif w == 'end'
      " use mathit
      normal %
      exe "normal! ciw{\<esc>``ciw}\<esc>"
    else
      throw 'Cannot toggle block: cursor is not on {, }, begin, nor end'
    endif
  endif
endfunction

Where lh#position#char_at_mark() is defined here.

PS: this is definitively a SO question as it combines ruby context, and advanced vim scripting.