val .finish = fn(.s) b2s map fn(.x) number(.x, 16), rest split "%", .s
val .decode = fn(.s) replace .s, re/(%[0-9A-Fa-f]{2})+/, .finish
writeln .decode("http%3A%2F%2Ffoo%20bar%2F")
writeln .decode("google.com/search?q=%60Abdu%27l-Bah%C3%A1")