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Re: Understanding 'chaining'

From: Ivan Herman <ivan@w3.org>
Date: Thu, 29 Nov 2007 17:03:17 +0100
Message-ID: <474EE2C5.1040205@w3.org>
To: Mark Birbeck <mark.birbeck@x-port.net>
Cc: Ben Adida <ben@adida.net>, RDFa <public-rdf-in-xhtml-tf@w3.org>
O.k, let me try to characterize the old/new model, just for my own
understanding (and to make the differences clear for myself):

- a bnode created by a @rel/@rev is 'used' as the object of a triple if
an only if it becomes 'used' somewhere down the tree as a subject.
Otherwise it is ignored (I mean, the corresponding triple with the
@rel/@rev is ignored). (This answers to the inconsistency or, say,
ugliness that you referred to in your mail.)

- an @about appearing on an element always creates a new start (both in
the current and the old/new model) going down in the tree but, in the
new model it also, sort of, replaces a bnode that might have been
generated by a @rel/@rev somewhere 'up' (ie, toward the ancestors) in
the tree (and generates the hanging triples accordingly).

And these two statements effectively characterize the differences. Mark,
is that correct?

What about the implementation concerns? I can clearly see how this can
be implemented in python or similar languages. It is a tiny bit more
complex than now (essentially, hanging triples have to be sent 'down' by
recursion and put into the triple stores only if the bnode is used), but
nothing really major. I am not sure it is very easy in XSLT but, I must
admit, I am a very bad XSLT programmer. It would be a good idea to check
that (as Danny proposed).



Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf

Received on Thursday, 29 November 2007 16:03:23 UTC

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