-- �^�����s����
function mkfunc (printfunc)
  return function ()
    for v = 1, 10 do
      printfunc (v)
      coroutine.yield ()
    end
  end
end

function printalpha (n)
  print (string.char (n + string.byte ("A") - 1))
end

function costat (c)
  return coroutine.status (c) == "suspended"
end

local c, d = coroutine.create (mkfunc (print)),
             coroutine.create (mkfunc (printalpha))

while costat (c) or costat (d) do
  coroutine.resume (c)
  coroutine.resume (d)
end

while true do
  coroutine.resume (c)
  coroutine.resume (d)
end