W3C home > Mailing lists > Public > uri@w3.org > April 2004

Re: Concern with URI normalization text; proposed change

From: Roy T. Fielding <fielding@gbiv.com>
Date: Tue, 6 Apr 2004 13:23:04 -0700
Cc: Graham Klyne <gk@ninebynine.org>, uri@w3.org, Pat Hayes <phayes@ihmc.us>
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Message-Id: <358EF7AC-8808-11D8-9CC7-000393753936@gbiv.com>

> For example, if a URI http:/example.org/namespace is used as an XML 
> Namespace the similar URIs HTTP:/example.org/namespace or
> http:/example.org:80/namespace are not names for the same XML 
> namespace.

Yes they are.  The processing algorithm does not need to consider them
to be the same name, but XML cannot change the meaning of a URI.

> Thus techniques on the comparison ladder other than byte-for-byte 
> comparison do not work for comparing namespace URIs when used for the 
> purpose of naming namespaces. This counterexample (and others, for 
> example from RDF), indicates that the sentence is false.

They work just fine for comparing namespaces.  What they don't work for
is testing compliance with W3C recommendations, for which only the
simplest form of comparison is recognized.  XML Namespaces accepts the
presence of false negatives without any harm to the processing model.
Additional normalization of the namespace URI will not be incorrect;
it just won't be very useful, since the purpose of namespace names
is to avoid name collisions, not ensure name consistency.

Received on Tuesday, 6 April 2004 16:23:11 UTC

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