function! RelLinesInit ()
	sign define l_0 text=-- texthl=Search
	let index=1
	while index<=70
		let sindex = (index < 10 ? "0" : "") . index
		exe "sign define l_" . index . " text=" . sindex . " texthl=Search"
		let index+=1
	endwhile
endfunction

function! RelLines ()
	call RelLinesClear()
	let lcur=line(".")
	let ltop=line("w0")
	let lbot=line("w$")
	let index=ltop
	while index <= lbot
		let inum=index-lcur
		let anum= inum < 0 ? -inum : inum
		if anum < 70
			exe "sign place " . (70 + inum) . " line=" . index . " name=l_" . anum . " buffer=" . bufnr("%")
		endif
		let index+=1
	endwhile
endfunction

function! RelLinesClear ()
	let index=0
	while index<=140
		exe "silent sign unplace " . index . " buffer=" . bufnr("%")
		let index+=1
	endwhile
endfunction

map <silent> <special> <F11> :call RelLines()

map <silent> <special> <F12> :call RelLinesClear()


call RelLinesInit()