Re: URI documents

Harald Tveit Alvestrand (
Tue, 06 Jan 1998 12:59:34 +0100

Message-Id: <>
Date: Tue, 06 Jan 1998 12:59:34 +0100
To: Dan Connolly <>
From: Harald Tveit Alvestrand <>
Subject: Re: URI documents
Cc: Larry Masinter <>,
In-Reply-To: <>

At 09:29 02.01.98 -0600, Dan Connolly wrote:

>Harald, it would help me out if you would
>please point out how it is that (b) is not a solution.
>I read it quite carefully and I find it satisfactory.

That's why it went to Last Call - at first glance I found it so too.
At second glance (and considering others' vehemence), I'm not 
sure at all.

>Since Larry asked, I'll (re-)state the W3C opinion: we're
>heavily invested in the notion of a single, extensible universal
>address space:

The problem, to my mind, is that we really have two deep axioms

- The class of identifiers that, roughly speaking, start with
  a short string and a colon, and go on in a charset-limited way.
  All the URI axioms you cite are axioms of that class.
- The class of identifiers that, in addtion to being of the first
  class, obey certain additional rules, such as hierarchy,
  hostname representation and so on.
  None of this is necessary for the URI axioms; they are vitally
  necessary for today's day-to-day usage of the World Wide Web.

(Everyone with me so far?)

There are people among us who think (I think) that the rules of the
second class are more a result of the history of the field than they
are a good design that should be followed in the future; in particular,
they want to make sure that nobody - BUT NOBODY - builds into their
software assumptions that all URLs that happen to look like "type 2"
can be treated like "type 2" URLs.

This separation is, I think, probably best served by having 2 different
documents, one for URIs giving the "type 1" rules and one giving
the "type 2" rules.

If this is the case, we have more issues:

- Is the #fragment rule a "type 1", "type 2" or "none of the above, but
  should be mentioned in both places"?
- For things that are currently called URLs, but don't follow the "type 2"
  rules, should we recategorize them as URIs or say that the URL concept
  embraces both "type 2" URIs and some other URIs?

If separation is not the Right Way, the issues are of course slightly

                                   Harald A