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Re: DTB status (on today's agenda)

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Tue, 29 Apr 2008 19:35:27 -0400
To: Axel Polleres <axel.polleres@deri.org>
Cc: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>
Message-ID: <15982.1209512127@cs.sunysb.edu>


> Michael Kifer wrote:
> >> Dear all,
> >>
> >> since DTB status is on the agenda today, I basically want to clarify in 
> >> the call today the following issues. I was anyway a bit occupied with 
> >> other things, but basically, I am still stuck, as long as these issues 
> >> are open, because any switch on them would mean unnecessary additional 
> >> work on editing over the whole document (as opposed doing it in one go 
> >> when they are clarified).
> >>
> >> ==============================================================================
> >>
> >>
> >> 1) As for CURIEs, is [1] a proposal which woulc achieve a majority?
> >> I would like it. I postponed further editing before the CURIE issues is 
> >> solved or before at least it was discussed in the Telconf., since I 
> >> don't want to change everything back again, when we decide something.
> >>
> >> I suggest to
> >>
> >> PROPOSE: Adopt the CURIE proposals of [1] for RIF's presentation syntax.
> >>
> >> [1] Sandro's final CURIE proposal: 
> >> http://lists.w3.org/Archives/Public/public-rif-wg/2008Apr/0134.html
> > 
> > As discussed, this still has the old problems that interpretation of the
> > macro : depends on the context and is too complex. Why not use a simple
> > concatenation macro and be done with it?
> 
> Well, don't think this is a problem if "marcos" ie. prefixes are not 
> expanded within quotes and angle brackets. Why ist is a problem if 
> quotes or angle brackets escape the macro expansion? Otherwise, you can 
> get ambiguities.
> 
> Axel

Here are the problems again:

   1.  Point Brackets

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

same as "http://purl.org/dc/terms/creator"^^rif:iri  - ok

   2.  CURIEs

    	 after:   PREFIX("dc", "http://purl.org/dc/terms/").

         dc:creator

presumably "http://purl.org/dc/terms/creator"^^rif:iri - ok

   3.  Data Value (using Pointy Brackets for rif:uri)

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

Not ok: <http://www.w3.org/2007/rif#iri> is supposed to stand for
"http://purl.org/dc/terms/creator"^^rif:iri, so we have context sensitivity
here.

   4.  Data Value (using CURIE rif:uri)

	 after:   PREFIX("rif", "http://www.w3.org/2007/rif#").

         "http://purl.org/dc/terms/creator"^^rif:iri

Context sensitivity. rif:iri here is supposed to stand for
http://www.w3.org/2007/rif#iri. But according to (2) above it stands for
"http://www.w3.org/2007/rif#iri"^^rif:iri.

If you are saying that rif:iri cannot be expanded into what it stands for
after the ^^ then it is even worse than context sensitivity.

In addition, I find the above rules too complex for me to retain in my
diminishing pool of long-term memory cells.
I prefer a simple macro that is akin to (but much simpler) than
C macros. XML entities is an example of this, but most people find them
ugly and they need to be defined in the presentation syntax anyway.
For instance,

    dc:creator^^rif:iri


    If the above is unacceptable, in the interests of moving things
forward, I think the following could be tolerated, although it is still
context-sensitive. It was proposed in the past by somebody (maybe not
exactly this):

1. After ^^ a curie expands by simple concatenation:

    "foobar"^^rif:iri
    -->
    "foobar"^^http://www.w3.org/2007/rif#iri

2. Standalone: expands into concatenation, enclosed in "..." and followed
   by ^^http://www.w3.org/2007/rif#iri:

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

This is simple enough and is sellable.

There is still an issue of what to do if somebody defines http as a prefix.
Also, leaving something like http://www.w3.org/2007/rif#iri hand around
without delimiters is problematic, especially since IRIs have many
different schemes. One possibility is to delimit these iris with single quotes:

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

or with double quotes.


	--michael  
Received on Tuesday, 29 April 2008 23:40:10 GMT

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