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Re: Comparable considered necessary

• To: xml-dev@l...
• Subject: Re: Comparable considered necessary
• From: Joe English <jenglish@f...>
• Date: Sun, 11 Aug 2002 08:42:34 -0700
• In-reply-to: <r01050300-1015-5B91DCF6ACD111D69D4E0003937A08C2@[192.168.124.21]>
• References: <r01050300-1015-5B91DCF6ACD111D69D4E0003937A08C2@[192.168.124.21]>

Simon St.Laurent wrote:
>
> I think the largest concrete problem I have with URIs is their lack of a
> common mechanism for saying this equals that.

Two URIs are equal if they are textually identical; that
much should be apparent.

IMO, the only sensible scheme is to strengthen this to 
"if _and only if_" they are textually identical.  Adding 
any other criteria starts down a very steep slippery
slope into unmanageable complexity.

> I can live without
> ordering for names, so that's not a big deal, but the lack of clarity on
> things like:
>
> HTTP://MONASTICXML.COM
> vs.
> http://monasticxml.com
> vs.
> http://monasticXML.com
>
> is pretty much killing, even without issues of relative and absolute,
> query strings, etc.

The only sensible thing to do is to treat all three of
these as distinct URIs.  One _could_ argue that since
the 'http' scheme uses a server-based naming authority,
and since hostnames are case-insensitive according to DNS,
that the latter two should be considered equal.

But there's that slippery slope:  according to DNS,
'monasticxml.org', 'www.monasticxml.org', and '66.45.6.211'
are _also_ equivalent (at least today).


> The lack of clarity - heck, the outright refusal to acknowledge the
> question - about how to get from an identifier to a resource or back
> again - is the nails in the coffin.

I disagree; refusing to acknowledge the question is the
only sensible thing to do.  Asking "Do these two URIs identify
the same resource?" is like asking "are the chair in my living
room and the chair in my dining room both shadows of the
same Platonic Chair?"  Better to unask the question; you
can't reliably get a useful answer.

"Are X and Y the same URI?" is answerable.  "Do X and Y identify
the same resource?" is not.


--Joe English

  jenglish@f...

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