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Re: Late, but possibly useful, comments on SPARQL Last Call WD

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Wed, 12 Apr 2006 10:51:30 +0100
Message-ID: <443CCDA2.1070702@hp.com>
To: Jim Melton <jim.melton@acm.org>
CC: public-rdf-dawg-comments@w3.org

Jim,

Thank you for the comments: changes noted and explanation as noted below:

Jim Melton wrote:
> Gentlepeople,
> 
> I offer my apologies for failing to submit comments on the most recent 
> SPARQL Last Call Working Draft [1] by the stated deadline.  I hereby submit 
> these mostly editorial comments in the hope that they may be useful even 
> though late.  I emphasize that these comments are my personal comments and 
> do not necessarily reflect the opinions of my employer (Oracle) or the 
> Working Group that I co-chair (XML Query WG).
> 
> 1) In section 1, Introduction, second paragraph, the first bullet currently 
> reads:
> 
>    * extract information in the form of URIs, blank nodes, plain and typed 
> literals.
> 
> I believe that the word "and" should be inserted immediate prior to the 
> word "plain"; otherwise, one might be misled into thinking that one could 
> "extract information in the form of plain".

Changed to "URIs, blank nodes and literals." as literals covers plain and 
typed RDF literals.

> 2) In section 2.1.2, Syntax for Literals, I note that "an optional language 
> tag (introduced by @)" is part of the syntax.  Am I the first person to 
> observe that XPath users may be discomfited by this convention, since the 
> "@" is used in that language as a shorthand notation to indicate an XML 
> attribute?  Surely there is another character or character sequence that 
> would not intrude on that XPath convention.

The choice of the "@" character is taken from commonly used in (non-XML) RDF 
serializations derived from N3 (N-Triples, Turtle).  The working group decided 
to use a syntax that meant that a piece of N3 or Turtle could be used as a 
template for placed in a query by replacing some RDF terms with variables.

> 3) In section 2.1.3, Syntax for Variables, I read: '...it is the same 
> variable everywhere in the query that the same name is used. Variables are 
> indicated by "?"; the "?" does not form part of the variable.'  There are 
> two things wrong with that text.  First, the phrase "it is the same 
> variable everywhere..." is awkward; I would suggest rephrasing that along 
> the lines of 'everywhere in a query that a given variable name is used, 
> that name identifies the same variable'.

Reworded as:

"""
Variables in SPARQL queries have global scope; use of a given name anywhere in 
a query identifies the same variable.
"""

   Second, the phrase 'the "?" does
> not form part of the variable' is a non-sequitor; I doubt that anybody 
> would think otherwise.  I believe that you meant to say 'the "?" does not 
> form part of the variable name'.

Reworded as:
"""
the "?" does not form part of the variable name.
"""

> 4) In section 2.2, Initial Definitions, the fifth paragraph claims "Note 
> that all IRIs are absolute."  This is in direct conflict with the 
> subheading in section 2.1.1, Syntax for IRIs, "Relative IRIs", and the text 
> that follows that subheading.  While I have no reason to dispute the 
> statement in section 2.2, the discrepancy must be resolved.

The difference is that the syntax allows relative IRIs : the parsing process 
will have to resolve these because RDF and SPARQL operate on absolute IRIs.

Section 2.1.1 does say that "SPARQL provides two abbreviation mechanisms for 
IRIs".  I have changed this to "The SPARQL syntax"

In 2.2 I added a sentence

"""
The abbreviated forms (relative IRIs and prefixed names) in the SPARQL syntax 
are resolved to produce absolute IRIs.
"""

> 5) In section 2.8.2, Object Lists, the second paragraph contains the word 
> "tripe" and the non-word "shodul"; "triple" and "should", respectively, 
> were intended.  Similarly, the phrase "one of the other" should be "one or 
> the other".

All tripe has been removed from the document.

Similar, the other typos are gone.

> 
> 6) In section 2.8.4, RDF Collections, the phrase "then triple patterns" is 
> used, but seems awkward at best.  Should this be "the triple patterns" or 
> merely "triple patterns"?

s/then triple patterns/triple patterns/


> 7) The second section 2.8.4, rdf:type, should probably be numbered 2.8.5.

Corrected (the TOC is already correct).

> 8) In the second section 2.8.4, rdf:type, the keyword "a" is 
> described.  That is a fairly unfortunate spelling, and it's probably too 
> late to do anything about it.  But I would have thought that "isA" would be 
> a much more obvious, and more readily pronounceable (in context), spelling.

Like "@" the use of keywrod "a" is yaken from N3 and dervives serializations 
of RDF.

> 
> 
> I regret that I am unable to continue my review at this time due to 
> overwhelming other commitments.

> 
> Hope this helps,
>     Jim
> 

Thank you for the time you have been able to find for review
of the SPARQL query language document.

	Andy

> [1] http://www.w3.org/TR/2006/WD-rdf-sparql-query-20060220/
> 
> ========================================================================
> Jim Melton --- Editor of ISO/IEC 9075-* (SQL)     Phone: +1.801.942.0144
>    Co-Chair, W3C XML Query WG; F&O (etc.) editor    Fax : +1.801.942.3345
> Oracle Corporation        Oracle Email: jim dot melton at oracle dot com
> 1930 Viscounti Drive      Standards email: jim dot melton at acm dot org
> Sandy, UT 84093-1063 USA          Personal email: jim at melton dot name
> ========================================================================
> =  Facts are facts.   But any opinions expressed are the opinions      =
> =  only of myself and may or may not reflect the opinions of anybody   =
> =  else with whom I may or may not have discussed the issues at hand.  =
> ========================================================================  
> 
> 
Received on Wednesday, 12 April 2006 09:51:48 GMT

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