Re: proposed changes to the rdf:text document for option 5

From: "Seaborne, Andy" <andy.seaborne@hp.com>
Subject: RE: proposed changes to the rdf:text document for option 5
Date: Thu, 28 May 2009 05:37:50 -0500

> 
> 
>> -----Original Message-----
>> From: public-rdf-text-request@w3.org [mailto:public-rdf-text-
>> request@w3.org] On Behalf Of Peter F.Patel-Schneider
>> Sent: 27 May 2009 16:26
>> To: public-rdf-text@w3.org
>> Subject: proposed changes to the rdf:text document for option 5
>> 
>> 
>> [Suggested change to Abstract - yes this is not part of option 5]
>> 
>> This document presents the specification of a datatype for plain
>> literals in RDF.
>> 
>> 
>> [Changes to two last paragraphs of Section 1]
>> 
>> To address these deficiencies, this specification introduces a datatype
>> called rdf:text, which uses the rdf: prefix because it refers to parts
>> of the conceptual model of RDF.  This extension, however, does not
>> change the conceptual model of RDF, and thus does not affect the
>> specifications that depend on the conceptual model of RDF such as
>> SPARQL.  The value space of rdf:text consists of all data values
>> assigned to RDF plain literals, which allows RDF applications to
>> explicitly refer to this set (e.g., in rdfs:range assertions).
>> 
>> Because RDF plain literals are already a part of RDF and SPARQL
>> syntaxes, rdf:text literals are always written as RDF plain literals in
>> RDF and SPARQL syntaxes.
>> 
>> 
>> [Change to entirely of Section 4
>>  - the last paragraph might need some tweaking]
>> 
>> 4 Syntax for rdf:text literals
>> 
>> It is obvious from the above that the value space of rdf:text contains
>> exactly all data values assigned to RDF plain literals (with or without
>> a
>> language tag).  The rdf:text datatype thus provides an
>> explicit way of referring to this set.
>> 
>> To eliminate another source of syntactic redundancy, the form of
>> rdf:text literals in syntaxes for RDF graphs and SPARQL basic graph
>> patterns is the already existing syntax for the corresponding plain RDF
>> literal, and not the syntax for a typed RDF literal.  Therefore, typed
>> literals with rdf:text as the datatype do not not occur syntaxes for RDF
>> graphs, nor in syntaxes for SPARQL basic graph patterns.
>> 
>> As a consequence of the above, applications that employ the rdf:text
>> datatype *MUST* use plain RDF literals when they transfer RDF graphs
>> (because there is no other way to write typed literals with datatype
>> rdf:text) and will retain a large degree of interoperability with
>> applications that do not understand the rdf:text datatype.
>> 
>> 
>> <em title="MUST in RFC 2119 context" class="RFC2119">MUST</em> 
>> 
>> peter
> 
> There are another 2 cases which, to my reading, are not covered here.
> 
> 1/ SPARQL Query Results XML Format
> 
> Suggestion: add this to the 
> 
> "do not occur syntaxes for RDF graphs"
> ==>
> "do not occur syntaxes for RDF graphs nor the SPARQL Query Results XML Format"
> 
> Ideally, add to the "MUST use" sentence as well but see below.
> 
> 2/ The results of matching a BGP matched using extending SPARQL Basic
> Graph Matching generates binding for variables.  This is not about the
> syntax of SPARQL.  It needs to be covered because the algebra and
> IFLTER functions work on these bindings. 
> 
> Suggestion:
> 
> "The results of matching SPARQL basic graph patterns in an entailment
> regime that understands rdf:text MUST provide variable bindings in
> existing RDF plain literal form." 
> 
> If this is included, then the explicit prohibition in SPARQL Query
> Results XML Format is not needed but the suggested informative note
> that the effect is there would be useful. 
> 
> 	Andy

I've put your Suggestion wording in place and have not changed the
earlier stuff.  The document might be in a slightly inconsistent state,
as I'm not sure how the other SPARQL wordings should change.

However, how about the following wording instead? 

   To eliminate another source of syntactic redundancy, the form of
   rdf:text literals in syntaxes for RDF graphs and SPARQL *queries,
   bindings, and results* 
   is the already existing syntax for the corresponding plain RDF
   literal, and not the syntax for a typed RDF literal.  Therefore, typed
   literals with rdf:text as the datatype do not not occur syntaxes for RDF
   graphs, nor in syntaxes for SPARQL *queries, bindings, or results*.

   As a consequence of the above, applications that employ the rdf:text
   datatype *MUST* use plain RDF literals when they transfer RDF graphs
   (because there is no other way to write typed literals with datatype
   rdf:text) and will retain a large degree of interoperability with
   applications that do not understand the rdf:text datatype.  Similar
   consequences apply to applications that use SPARQL.

It might be better to just remove the **'d qualifiers, however.


A possible augmentation would be to add examples, perhaps

   e.g., RDF/XML [?] and Turtle [?],
   e.g., the SPARQL query language syntax [?] and the SPARQL query results
   	 XML format [?]

to the appropriate places in the first paragraph.

peter

Received on Thursday, 28 May 2009 13:30:04 UTC