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Re: URI versus URI Reference

From: John Cowan <jcowan@reutershealth.com>
Date: Wed, 24 May 2000 16:17:13 -0400
Message-ID: <392C38C9.2D9C37BA@reutershealth.com>
To: abrahams@acm.org, "xml-uri@w3.org" <xml-uri@w3.org>
"Paul W. Abrahams" wrote:

> I don't think that RFC2396 actually says that a URI has to be
> absolute.  A URI has to identify a resource, but RFC2396 nowhere
> says explicitly that the identification has to be
> context-independent.

As we have seen, some absolute URIs (or just URIs) are *not* context-
independent, e.g. "mailto:jcowan".

>   But to say that a URI has to be absolute
> also runs up against the existence in RFC2396 of the nonterminal
> relativeURI (defined in Sec. 5) and the fact that Section 3 speaks
> of absolute URIs.   I suppose one could argue that a relativeURI
> isn't a URI at all, but that's certainly counterintuitive.

That is the language of 2396.

>  And why
> would Section 3 have to refer to absolute URIs if there aren't any
> other kinds of URIs?

Clarity.  Prior to 2396, there was much talk of "relative URIs";
2396 established that what was previously called a "relative URI"
was now to be called a "relative URI reference".

> There's also the fact that in programming languages, ref x is not
> the same as x, not even syntactically (modulo implicit
> dereferencing, of course).

Fee, fie, fo, fum, I smell another ALGOL 68 aficionado!

>  One would expect a URI reference to be
> a pointer to a URI, i.e., a doubly indirect specification of a
> resource, and not some generalization or specialization of a URI.

In a sense, "foo" is a pointer to the actual URI, but it's what
PL/I called a BASED pointer, one that only makes sense relative
to a certain base.

-- 

Schlingt dreifach einen Kreis um dies! || John Cowan <jcowan@reutershealth.com>
Schliesst euer Aug vor heiliger Schau,  || http://www.reutershealth.com
Denn er genoss vom Honig-Tau,           || http://www.ccil.org/~cowan
Und trank die Milch vom Paradies.            -- Coleridge (tr. Politzer)
Received on Wednesday, 24 May 2000 16:21:41 UTC

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