[.vimrc] toggle between CamelCased/under_scored word

gistfile1.vim

" TODO when no keyword is under/after the cursor, try looking backward to find a word.
fun! WordTransform()
  let w = expand("<cword>")
  let x = ''
  let c = strpart(getline('.'), col('.') - 1, 1)
  if match(w, '_') > -1
    let x = substitute(w, '_\([a-z]\)', '\u\1', 'g')
  else
    let x = substitute(w, '\C[A-Z]', '_\L\0', 'g')
  endif
  if x == w
    echohl WarningMsg | echomsg "Not a camelCased/under_scored word." | echohl None
    return
  endif
  if match(w, c) < 0   " cursor might sit before keyword
    exec "normal f" . strpart(w, 0, 1)
    exec "normal \"_ciw\<C-R>=x\<CR>"
  else
    exec "normal \"_ciw\<C-R>=x\<CR>"
  endif
endf
nnoremap <LocalLeader>x :call WordTransform()<CR>