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Re: Unseasonal, maybe: But what is the URI for "null"?

From: Al Gilman <asgilman@iamdigex.net>
Date: Wed, 02 Jan 2002 13:35:20 -0500
Message-Id: <Version.32.20020101121930.04000910@pop.iamdigex.net>
Message-Id: <Version.32.20020101121930.04000910@pop.iamdigex.net>
To: uri@w3.org
Cc: tony_hammond@harcourt.com
At 08:47 AM 2001-12-23 , tony_hammond@harcourt.com wrote:
>Please excuse if this is a FAQ.
>
>But is there a URI for a (I guess that should be "the") null resource?
>

* the bad news

One plausible reading of RFC-2396 would lead one to conclude that:

 There is a definition of what it is to be a URI but not what it is to be a
resource.  

I say "one plausible reading" because it is not clear you will find consistent
agreement with this statement.  On the other hand, it is not clear you will
find a convincing counter-argument, either.

If the notion of "a resource" is undefined, then the notion of "a null
resource" is undefined, and a_fortiori "the null resource."  Nulls may make
sense in more restricted contexts, but not in the full generality of "anything
that could be indicated by a URI."

* the good news

There are many fictive URIs one can coin using the reserved domain names of
RFC-2606, such as

<cid:garbageStringOfYourChoice@mail.example.net> and
<urn:example.org:topic:aspect:nit>.

Authoring these expressions, and presuming that the reader (man or machine) of
these expressions is conversant with DNS and its RFC-2606 provisions, one can
be reasonably assured that the reader will understand that the string
conforming to URI syntax that you have written indicates nothing more than the
utterance (containing this string) itself, without connoting the existence of,
or referring to, further resources beyond the writing at hand.

Hopefully, if you have an application for a "null resource" URI, this
technique
will meet your need.

* discussion

What were you thinking it would mean to be "a null resource"?  The notions of
nullity that I am familiar with bear operational connotations.  Zero is a
number such that when you add it to a number, in the end you haven't changed
that number.  URIs define what it is to be a URI, but not what it is to be a
resource.  So what it would be to be a non-entity through the lens of the
domain of resources is similarly undefined, as best I can figure out.

To say that something is "content free" would require a reproduceable test for
the presence/existence of 'content.'  URIs _per se_ do not provide such a
test.

Beauty, it is said, is in the eye of the beholder.  Likewise, the conditions
for resource-ness are left to other concerns from the context of application,
at least as far as what is defined about URIs in general is concerned.

Al

<http://www.ietf.org/rfc/rfc2606.txt>http://www.ietf.org/rfc/rfc2606.txt
etc.

>Cheers,
>Tony
>  
Received on Wednesday, 2 January 2002 13:20:06 GMT

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