Re: URI versus URI Reference

Yes, as you concluded from John Cowan's response, the relative/absolute
language in the URI RFC is syntactic in nature and addresses different
forms of identifier-expression that may appear in (relative) more
restricted or (absolute) more general contexts.

For the record, another discussion below:


At 01:47 PM 2000-05-26 -0400, Paul W. Abrahams wrote:
>John Cowan wrote:
>> "Paul W. Abrahams" wrote:
>> > ``A Uniform Resource Identifier (URI) is a compact string of
characters that
>> > identifies an abstract or physical resource.  A URI is absolute, i.e.,
its meaning
>> > does not depend on the context in which it appears.''
>> The first sentence is true and useful.  The second sentence is false: a URI
>> *is* absolute, but is not therefore necessarily independent of its context,
>> as in the case of mailto: and file: URIs.
>OK.  Can you come up with a replacement for the i.e. that describes, in a
short simple
>phrase, what ``absolute'' means?   Or (this is the possibility I dread) is
it the case
>that we don't really know what it means?
>Paul Abrahams

Actually, it is easiest to start by defining what 'relative' means.  

The relativeURI syntax defines an abbreviated variant class of
identifier-expression which may be used in a suitable Document Context
which provides the required BASE context property by which to de-localize
the identification of a resource by the transformation defined in the RFC.

An absoluteURI is another class of identifier-expression which is free of
any dependency on the BASE based de-localization transformation.

The effect is that an absoluteURI is fully as usable in the net just
outside the current Document Context as it is within that context.

Warning:  Document Context is a Term of Art:  see the discussion of how the
BASE value is determined.  The fact that email tools will in fact deliver
mail where the mailto: URL failed to contain a syntactically-conforming
mailbox address is net-protocol stuff outside the range of issues the
absolute/relative distinction in URI-reference syntax considers. 


Received on Friday, 26 May 2000 15:37:48 UTC