(fn table.clone [tbl]
  (let [newtbl {}]
    (each [k v (pairs tbl)]
      (tset newtbl k v))
    newtbl))
(fn string.fromhex [str]
  (str:gsub ".." (fn [cc] (string.char (tonumber cc 16)))))
(fn string.tohex [str]
  (str:gsub "." (fn [c] (string.format "%02X" (string.byte c)))))