First, I think the code's a good start at cleaning up the Url code.

The tests all pass in my 3.8g-6550 image.

And, provided you use my toText->asString changeset, Scamper's happy
with the changes.

Now time for my "but": I think we need some sort've mechanism so
packages can add to the list of known URLs. For instance, my SIP package
uses a SipUrl, and currently that package changes Url's code directly
(in an analogous way to HttpUrl and friends).

Mind you, maybe that's something for the next changeset! (One of my
first thoughts was having something in SubclassOfUrl class>>initialize
add to a collection in Url.

frank