W3C home > Mailing lists > Public > www-rdf-logic@w3.org > May 2001

Re: DAML+OIL bug

From: Dan Connolly <connolly@w3.org>
Date: Tue, 22 May 2001 10:41:09 -0500
Message-ID: <3B0A8895.EF0C15D3@w3.org>
To: Drew McDermott <drew.mcdermott@yale.edu>
CC: www-rdf-logic@w3.org
Drew McDermott wrote:
[...]
>    [[[
>    4. URI References
> 
>       The term "URI-reference" is used here to denote the common usage of a
>       resource identifier.  A URI reference may be absolute or relative,
>       and may have additional information attached in the form of a
>       fragment identifier.
>    ]]]
> 
> Okay, more research has turned up the following, from
> 
> http://www.w3.org/Addressing/URL/4_2_Fragments.html

Er.. that's really old. It's obsoleted by RFC2396.

> which is a section of
> 
> http://www.w3.org/Addressing/URL/URI_Overview.html
> 
> by Tim Berners-Lee:
> 
>    The fragment-id follows the URL of the whole object from which it is
>    separated by a hash sign (#). If the fragment-id is void, the hash
>    sign may be omitted: A void fragment-id with or without the hash sign
>    means that the URL refers to the whole object.
> 
> So
> xmlns:foo="http://random.org/expl#"
> 
> and
> 
> xmlns:bar="http://random.org/expl"
> 
> use the *same* URI written two different ways,

Not by current specs. The first one isn't a URI, strictly
speaking. They're both URI references; the first one
has an empty fragment and the second one has no fragment.

(ask Fielding via uri@w3.org if you'd like more details.)

> and hence define the
> same namespace.

Nope; the XML namespace spec is pretty clear: if the namespace
name strings are different, you're not licensed to assume
they're the same namespace.

[it doesn't even allow for converting relative URI references
to absolute form, which I consider a bug, but that's
on hold.]

>  So Allegro's parser should not complain when it sees
> the trailing #,

Right.

> although it could discard it.

Nope.

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 22 May 2001 11:41:11 UTC

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