W3C home > Mailing lists > Public > public-rif-wg@w3.org > April 2008

Re: DTB status (on today's agenda)

From: Sandro Hawke <sandro@w3.org>
Date: Tue, 29 Apr 2008 20:47:36 -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: <3397.1209516456@ubuhebe>


> 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

Yes, but that's not fully expanded.  The proposal is that the
fully-expanded syntax is

     " ...data value serialization... "^^<  ... uri of datatype ... >

The less-than and greater-than can be considered as part of the ^^
operator.

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

>    2.  CURIEs
> 
>     	 after:   PREFIX("dc", "http://purl.org/dc/terms/").
> 
>          dc:creator
> 
> presumably "http://purl.org/dc/terms/creator"^^rif:iri - ok

(same comment as above)

>    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.

I assume you meant:

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

Well, yes -- in the sense that the pointy-brackets in the wild
 
   ...   <stuff>  ...

get turned into

   "stuff"^^<http://www.w3.org/2007/rif#iri>

while pointy brackets after the ^^ just stay there, as part of the
non-CURIE syntax of ^^.

>    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.

Well, sort of.   

rif:iri turns into <http://www.w3.org/2007/rif#iri>

and pointy-brackets on the right side of ^^ don't get further expanded.

> 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 am hugely sympathetic to this argument.   :-/

> 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 quote
> s:
> 
>     "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).

       -- Sandro
Received on Wednesday, 30 April 2008 00:49:17 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 2 June 2009 18:33:48 GMT