val finish = fn s:b2s(map(
    less(split(s, by="%"), 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("https%3A%2F%2Fno%20more%20foo%20bars%20please%2F")
writeln decode("google.com/search?q=%22unbroken%20string%22")