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Re: DTB status (on today's agenda)

From: Sandro Hawke <sandro@w3.org>
Date: Thu, 01 May 2008 22:55:38 -0400
To: kifer@cs.sunysb.edu (Michael Kifer)
Cc: Axel Polleres <axel.polleres@deri.org>, "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>
Message-ID: <13560.1209696938@ubuhebe>


> > >     "http://purl.org/dc/terms/creator"^^'http://www.w3.org/2007/rif#iri'
> > > 
> > > or with double quotes.
> > 
> > Yeah, or the standard URI delimiter characters "<" and ">".
> > 
> > I could live with double quotes, but I (and perhaps you) will get a lot
> > of WTF looks from people who see we took ^^ from N3/N-Triples/Turtle and
> > then oddly used quotes for URI delimiters instead of "<" and ">".  If we
> > use double quotes, I might suggest we change from a^^b to something like
> > datavalue(a,b).
> 
> 
> This is why I think it is better to leave it underspecified and let people
> use their imagination. First, our spec allows for aliases to symbol spaces
> and aliases do not need to be IRIs (only the main identifiers). So, it
> would be strange to write
> 
> "http://purl.org/dc/terms/creator"^^<http://www.w3.org/2007/rif#iri>
> vs
> "http://purl.org/dc/terms/creator"^^foobar

That doesn't seem at all strange to me, in the style of N3-inspired
languages that use URIs (surrounded by "<" and ">") as terms.  I expect
to be able to use these...

      <http://purl.org/dc/terms/creator>
      dc:creator
      myCreator        [ a local term ]
      ?myProp          [ a variable ]

in the same positions in the grammar, in general.  (Obviously there may
be some restrictions, like variables in the predicate position.)
      
> Second, our presentation syntax, not being a concrete syntax, is lacking in
> details in many other ways, so why should we spend so much time filling in
> the details of this particular piece of syntax?

I hear that you don't think this is important, but several other WG
members think this particular bit of the syntax it is quite important to
nail down.  Do you think it has to take much more time?     I'm hearing
that you find this distasteful, but not that it's actually broken.

> Third, I think that <http://www.w3.org/2007/rif#iri> 
> should stand for "http://www.w3.org/2007/rif#iri"^^rif:iri, since

You mean, even on the right side of the ^^ ?    

You don't like

  "http://purl.org/dc/terms/creator"^^<http://www.w3.org/2007/rif#iri>

because it should be

  "http://purl.org/dc/terms/creator"^^"http://www.w3.org/2007/rif#iri"^^rif:iri

?

My point is that you have to end the recursion somewhere, and N3 ends it
at terms like <...>. 

So I see two decent options:

      1.   Allow a new kind of Const, with the syntax '<'+urichar*+'>',
           which is understood to mean exactly the same thing as
           '"'+urichar*+'"' with the symbol space identified by the URI
           "http://www.w3.org/2007/rif#iri".  But we don't rewrite it
           that way, because we'd have infinite recursion.  Instead of:
 
                "http://purl.org/dc/terms/creator"^^
                   "http://www.w3.org/2007/rif#iri"^^
                     "http://www.w3.org/2007/rif#iri"^^
                        "http://www.w3.org/2007/rif#iri"^^
                            ...
 
           we can chop it any point, like:

                "http://purl.org/dc/terms/creator"^^
                   "http://www.w3.org/2007/rif#iri"^^
                     <http://www.w3.org/2007/rif#iri>

           or:

                "http://purl.org/dc/terms/creator"^^
                   <http://www.w3.org/2007/rif#iri>

           or, of course, just:

                <http://purl.org/dc/terms/creator>

      2.   <foo> expands to

               lit("foo", "http://www.w3.org/2007/rif#iri")

           a:b expands to         

               lit( concat(expand(a), expand(b)),
                    "http://www.w3.org/2007/rif#iri"  )

Do both of these make sense?   I'd imagine you prefer the latter, but
can you live with them both?

        -- Sandro

> in turtle these things are analogous rif iri's 
> (in RIF http://www.w3.org/2007/rif#iri is something that happens to look
> like a URI, which "http://www.w3.org/2007/rif#iri"^^rif:iri is an IRI).
Received on Friday, 2 May 2008 02:57:31 GMT

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