RosettaCodeData/Task/URL-decoding/Bracmat/url-decoding.bracmat

(     ( decode
      =   decoded hexcode notencoded
        .   :?decoded
          &   whl
            ' ( @(!arg:?notencoded "%" (% %:?hexcode) ?arg)
              & !decoded !notencoded chr$(x2d$!hexcode):?decoded
              )
          & str$(!decoded !arg)
      )
    & out$(decode$http%3A%2F%2Ffoo%20bar%2F)
);