function readln()
 local s=""
 h("display","|")
 while true do
  if ev[1] == "key_down" then
   if ev[3] == 13 then
    h("display","\127\n") return s
   elseif ev[3] == 8 then
    if s:len()>0 then s=s:sub(1,-2) h("display","\127\127|") end
   elseif ev[3] > 31 and ev[3] < 127 then
    s=s..string.char(ev[3]) h("display","\127"..string.char(ev[3]).."|")
   end
  end
  C.yield()
 end
end