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Re: Posted draft of URI comparison finding

From: Tim Bray <tbray@textuality.com>
Date: Wed, 11 Dec 2002 08:28:03 -0800
Message-ID: <3DF76793.6080105@textuality.com>
To: Chris Lilley <chris@w3.org>
Cc: www-tag@w3.org, David Orchard <dorchard@bea.com>

Chris Lilley wrote:
> On Saturday, November 30, 2002, 12:54:30 AM, David wrote:
> 
> DO> I think this is an excellent idea.  We should also make sure that we have
> DO> these comparison types easily referencable from other specifications.  This
> DO> way specs could easily refer into the comparison types.
> 
> Here is another comparison type (hostname case insensitive, optional
> default portnumber)

Er Chris, I think the draft kind of covered that.  Did you read through 
to the end?
...
> 
> Perhaps this gives a very practical tie-in to
> http://www.w3.org/TR/2002/WD-webarch-20021115/#URI-scheme
> 
> which used to say not to use unregistered schemes, but now does not
> (because testing requires use before registration).

Yep.  Let's get them stabilized and revisit.

> Which requires accepting that URI comparison is, indeed, specification
> specific. Whether two URIs are equivalent depends on why you want to
> know, and what you plan to do with the information. This makes me
> uncomfortable - I had some sympathy for TimBLs assertion that URI
> comparison is not spec specific - but equally, there are such a wide
> range of circumstances where URIs are compared. The constraints and
> expected results for comparing two namespace URIs  are not the same
> as, for example, a proxy cache comparing the incoming URI request with
> what resources (including variants and etags and last modify dates) it
> has in its cache.

Once again, I think the draft says that.

> TimB, in your document, section entitled "Rules Governing URIs" the
> first two paragraphs talk of characters and the third skips on to
> bytes without examining the relationship between the two. I agree that
> RFC 2396 has the same mistake, hence the need for IRI, but the
> ambiguity should at least be noted in passing in that section, I feel.
> Its treated later, right at the end of '%-Escaping Issues' but that is
> too late to introduce such an important concept.

Right, work needed, also in light of MDuerst's explication of %-escaping 
issues.

> If the hex-aware string comparison scheme was used, then an appendix
> could provide an unambiguous and authoritative fully hexified form of
> the namespace URI, for incorporation into software; it would match the
> unhexified or partially-hexified form correctly and since it used only
> 0-9 a-f and % it would be typographicaly unambiguous even when
> printed.

Good point. -Tim
Received on Wednesday, 11 December 2002 15:10:43 GMT

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