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RE: draft-kindberg-tag-uri

From: Martin Duerst <duerst@w3.org>
Date: Sun, 05 Sep 2004 10:15:51 +0900
Message-Id: <4.2.0.58.J.20040905095942.05e17728@localhost>
To: Larry Masinter <LMM@acm.org>, uri@w3.org
Cc: Tim Kindberg <timothy@hplb.hpl.hp.com>

Hello Larry,

Many thanks for your comments, which I think are quite
to the point.

At 10:52 04/09/04 -0700, Larry Masinter wrote:

> > What is it I'm missing in thinking that (URI) tags containing
> > pct-encoded characters are:
> > (a) self-defeating -- tags are supposed to be tractable for humans
> > (b) redundant -- it's never necessary to turn a tag containing, say,
> > Chinese characters into URI form; we need be sure only that it's in
> > canonical form and thus comparable with other tags.
>
>This makes it look like 'tag' doesn't have general applicability
>as a URI, as it can not generally be used in contexts that accept
>URIs but do not accept IRIs.
>
>Perhaps, in the transition from URIs to IRIs, it would
>make sense to allow new URI schemes to be registered that have
>this property, but it seems unnecessarily limiting.

Yes. I have tried to mitigate this problem a bit by suggesting to Tim
that the following rules be added/clarified in the draft:

- When generating TAGs (either US-ASCII only or beyond), never
   use %-encoding.
- When converting back from a place where only URIs are allowed
   (e.g. your example below), try to convert from URIs back to
   IRIs (i.e. get rid of the %-encoding).

This doesn't solve the problem completely, but hopefully
does alleviate it. It's still a good idea to say that
TAGs are designed to work best in contexts where IRIs
are allowed.


>It might be useful, as an informational adjunct to the IRI
>draft, to do a survey of URI contexts and the state of
>application for use of IRIs in those contexts, e.g., within
>HTML, inside email headers, in SIP, etc.
>
>For example, RFC 3106, ECML, has a "URI indicating version
>of this set of fields."  Can this actually be an IRI? I don't
>think RFC 3106 allows that. Can you use a Chinese 'tag' here?
>Not unless you allow pct-encoded characters.
>
>I just picked ECML at random;

Yes, it's probably not a very important example, as the
number of versions for ECML won't be very big, and the
newly defined version URIs will most probably be in
all-ASCII for world-wide usage.


>I think there are lots of other
>protocols that use 'URI' and would need their definition
>to be upgraded to allow 'IRI'.

Yes.


Regards,    Martin.
Received on Sunday, 5 September 2004 01:16:04 GMT

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