val finish = fn(s) {
  b2s(map(
      less(split(s, delim="%"), of=1),
      by=fn(x) { number x, fmt=16 },
      ))
    }
val decode = fn(s) {
  replace(
      s,
      by=re/(%[0-9A-Fa-f]{2})+/,
      with=finish,
      )
  }

writeln decode("http%3A%2F%2Fno%20more%20foo%20bars%20please%2F")
writeln decode("google.com/search?q=%22unbroken%20string%22")