Grep stuff inside Vim

simple-grep.vim

" grep!
function! s:ToggleQuickFix()
  if empty(filter(getwininfo(), 'v:val.quickfix'))
    copen
  else
    cclose
  endif
endfunction

function! s:Grepper(type)
  let l:bkreg=@@
  if a:type ==# 'v'
    normal! `<v`>y
  elseif a:type ==# 'char'
    normal! `[y`]
  endif
  silent exe "grep! -R " . shellescape(@@) . " *"
  let @@=l:bkreg
  copen
endfunction

nn <leader>qf :call <SID>ToggleQuickFix()<cr>
nn <leader>gg :set opfunc=<SID>Grepper<cr>g@
vn <leader>gg :<c-u>call <SID>Grepper(visualmode())<cr>