The (www url-coding) module provides two procedures for decoding
and encoding URL strings for safe transmission according to RFC 1738.
— Procedure: url-coding:decode str
Return a new string made from url-decoding str. Specifically,
turn + into space, and hex-encoded %XX strings into
their eight-bit characters.
— Procedure: url-coding:encode str reserved-chars
Return a new string made from url-encoding str,
unconditionally transforming those in reserved-chars, a list
of characters, in addition to those in the standard (internal) set.