.vimrc

function! AckSnippets(search)
    let ft = &ft
    if ft == 'objc' || ft == 'cpp' || ft == 'cs'
        ft = 'c'
    elseif ft == 'xhtml'
        ft = 'html'
    endif

    let dirs = join(split(
               \   globpath(g:snippets_dir, ft)."\n".
               \   globpath(g:snippets_dir, ft.'-*'),
               \ "\n"), ' ')

    let grepprg_bak=&grepprg
    exec "set grepprg=" . g:ackprg
    execute "silent! grep! -a " . a:search . ' ' . dirs
    botright copen
    let &grepprg=grepprg_bak
    exec "redraw!"
endfunction
command -nargs=? Acks call AckSnippets('<args>')