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RE: SPARQL 2004-10-12 syntax and grammar issues

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Mon, 8 Nov 2004 14:08:03 -0000
Message-ID: <8D5B24B83C6A2E4B9E7EE5FA82627DC94D313A@sdcexcea01.emea.cpqcorp.net>
To: "Dave Beckett" <dave.beckett@bristol.ac.uk>, "RDF Data Access Working Group" <public-rdf-dawg@w3.org>

> ISSUE: grammar lex/yacc shift/reduce conflicts
> I raised this in:
>
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004Jul/0016.html
> based on an IRC chat.  No reply so far.  The first shift/reduce
> conflict I think is serious.

This link points doesn't point to a message by Dave Beckett.  Nor is it
about lex/yacc shift/reduce conflicts.

	Andy

-------- Original Message --------
> From: Dave Beckett <>
> Date: 8 November 2004 12:15
> 
> Pulling my thoughts together in one email, my overall general concern
> is that the language is already too large and still growing.  I
> expected a strawman language based on BRQL to be removing things as
> well as adding them.
> 
> I've seen a tendency to when given two choices, pick both.  Which has
> been making the language larger and full of syntactic sugar or a
> sugary mess if you like.  This is a flaw of RDF/XML that I see
> starting to be repeated here.
> 
> There are lots of items in this email, several of which I've brought
> up in different places and I include pointers.  I'll put ISSUE:
> before each one I find significant.  I could pull them out into
> separate subject threads - my preference for tracking, but spawning
> 6-7 new threads.
> 
> Dave
> 
> -----
> 
> ISSUE: Variables with $ or variables with ?
> After the telcon discussion and preferences (vote?), I'm still
> waiting for the editors to announce what they are doing / have done.
> 
> The 2004-10-26 telcon
>  
>
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004OctDec/0194.html
> had strawpoll approximately  no preference: 4  $: 5+1ish  ?: 1
> which I saw as favouring $ alone.
> 
> 
> ISSUE: PrefixDecl allowed before or after Select
> After my posting:
>  
>
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004OctDec/0161.html
> and proposal:
>  
>
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004OctDec/0164.html
> and the telcon discussion 2004-10-26:
>  
>
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004OctDec/0194.html
> still waiting for any (if any) grammar change to be announced.
> 
> 
> ISSUE: Comments in SPARQL - /**/ // OR # OR both
> My initial posting
>  
>
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004OctDec/0199.html
> waiting for the editors to announce if there are any document changes.
> I don't actually see any decision in the last telcon minutes
>  
>
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004OctDec/0210.html
> 
> 
> ISSUE: Commas or no commas
> I've already seen user confusion when they tried to use ','s inside
> WHERE (s, p, o) and omitting them outside with SELECT ?x ?y.  I've
> mentioned this many times as likely to happen.  It's hard to remember.
> 
> 
> ISSUE: OPTIONAL or []s
> I've asked several times to pick just one of these.  The WG looked
> favourably at F2F on a syntax containing the latter only.  This
> is related to the more general need for a grouping construct - not
> needed at all if nested optionals are ditched.
> 
> 
> ISSUE: Keywords to be allowed in upper and lowercase
> 
> Breaking with the trend, I'd like an alternative.
> I'd like 'select' to be allowed as well as 'SELECT' for all keywords
> since stylistically uppercase "shouting" is getting tiresome and this
> is already done in RDQL, BRQL, SQL* languages and grammaras.  Note:
> This is NOT about making them case independent, allowing 'sElECt'.
> 
> 
> ISSUE: SPARQL EBNF / grammar detail suggestions
> I gave some layout suggestions in
>  
>
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004JulSep/0524.html
> some of which were added.
> 
> Since then I've been through all the grammar in detail and I've got
> more detailed suggestions:
> 
> * Add a grammar terms SelectClause, ConstructClause, DescribeClause
>   as part of ReportFormat.
> 
> * To make things easier for me in lex/yacc I renamed things that were
>   0 or 1 (not lists) to be ThingOpt - it'd be nice if that was used,
>   but just a suggestion.  I renamed FromClauseOpt, WhereClauseOpt.
> 
> * Non-terminals used only once.
>   I deleted FromSelector and others as they are used once only as an
>   alias for another non-terminal.  My preference to just put the
>   non-terminal in FromClause.  (The particular non-terminal may
>   change since it's related to the prefix issue - could be QuotedURI
>   or URI.)
> 
>   PatternElement1 and SingleTriplePatternOrGroup are also used once
>   only.
> 
> * I'm still not clear what GraphPattern1, PatternElementForms... are
>   for.  I re-arranged and merged many non-terminals [6]-[14] just for
>   my convenience.
> 
> * [12] PatternElementForms - 'SOURCE *' - I asked this before:
>     
>  
>
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004OctDec/0025.html
> Please explain where this syntax comes from and what it means.  
> 
> * Use shorter EBNF: [15] TriplePatternList ::= TriplePattern
>   TriplePattern* can be written more concisely as TriplePattern+
>   Similarly for other lists such as GraphPattern.
> 
> * I added VarOrURIList, VarList and URIList terms to handle the
>   optional comma messes.
> 
> * Several things inside the expression evaluation can be merged with
>   little loss - ConditionalOrExpression into Expression,
>   StringEqualityExpression into ValueLogical, StringComparitor into
>   StringEqualityExpression, RelationalComparitor into
>   EqualityExpression, NumericComparitor into RelationalExpression,
>   AdditiveOperation into AdditiveExpression, MultiplicativeOperation
>   into MultiplicativeExpression, PrimaryExpression into
>   UnaryExpressionNotPlusMinus, NumericLiteral/TextLiteral both into
> Literal 
> 
> * Use more of XML's EBNF and fix things up to match
>     http://www.w3.org/TR/2004/REC-xml11-20040204/#sec-notation
>   Use the correct syntax for terminals; <NAME> is not allowed as
>     symbol name in XML's EBNF.
>   [51], [61] ["A"-"Z"] is not legal.
>   [54] ["x", "X"] is not legal.
>   [57] ~[">", " "] is not legal
>   [48] (<NCNAME>)? doesn't need the ()s, similar in [59].
>   [51] <A2Z> is missing an open < or has an extra trailing >
> 
> 
> ISSUE: grammar lex/yacc shift/reduce conflicts
> I raised this in:
>   http://lists.w3.org/Archives/Public/www-archive/2004Jul/0016.html
> based on an IRC chat.  No reply so far.  The first shift/reduce
> conflict I think is serious.
Received on Monday, 8 November 2004 14:09:18 GMT

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