.vimrc

function! DrupalImplementsComment ()
  let filename = bufname("%")
  let dot = stridx(filename, ".")
  let module = strpart(filename, 0, dot)
  let current_line = getline(".")
  let hook_idx = matchend(current_line, "function " . module . "_")
  if !empty(module) && hook_idx != -1
    let hook_length = match(current_line, "(") - hook_idx
    let hook_name = strpart(current_line, hook_idx, hook_length)
    call DoxygenComment ("Implements hook_" . hook_name . "().")
  else
    call DoxygenComment ()
  endif
endfunction

function! DoxygenComment (...)
  set paste
  let message = (a:0 > 0) ? a:1 : ''
  exe "normal! O/**\<CR>"
    \ . " * " . message . "\<CR>"
    \ . " */\<Esc>"
  if empty(message)
    -1 | startinsert!
  else
    +1
  endif
  set nopaste
endfunction
noremap <leader>d :call DoxygenComment ()<CR>
noremap <leader>c :call DrupalImplementsComment ()<CR>