gistfile1.vim

let counter = 0 
inoremap <expr> <C-L> ListItem()
inoremap <expr> <C-R> ListReset()

func! ListItem()
  call cursor(line("."), 1)
  let g:counter += 1
  let texts = split(getline(line(".") -1), '\.')

  if len(texts) == 2                                                                                                                                           
    return g:counter . '.' . texts[1] . "\n"
  else
    return g:counter . '.' . "\n"
  endif
endfunc

func! ListReset()
  let g:counter = 0 
  return ''
endfunc