function! ToggleQuickfix(size, ...)
	let l:mode = (a:0 == 0)? 2 : (a:1)
	function! s:WindowCheck(mode)
		if &buftype == 'quickfix'
			let s:quickfix_open = 1
			return
		endif
		if a:mode == 0
			let w:quickfix_save = winsaveview()
		else
			if exists('w:quickfix_save')
				call winrestview(w:quickfix_save)
				unlet w:quickfix_save
			endif
		endif
	endfunc
	let s:quickfix_open = 0
	let l:winnr = winnr()
	noautocmd windo call s:WindowCheck(0)
	noautocmd silent! exec ''.l:winnr.'wincmd w'
	if l:mode == 0
		if s:quickfix_open != 0
			silent! cclose
		endif
	elseif l:mode == 1
		if s:quickfix_open == 0
			exec 'botright copen '. ((a:size > 0)? a:size : ' ')
			wincmd k
		endif
	elseif l:mode == 2
		if s:quickfix_open == 0
			exec 'botright copen '. ((a:size > 0)? a:size : ' ')
			wincmd k
		else
			silent! cclose
		endif
	endif
	noautocmd windo call s:WindowCheck(1)
	noautocmd silent! exec ''.l:winnr.'wincmd w'
endfunc

nmap <silent> <F12> :call ToggleQuickfix(0)<CR>