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

From: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
Date: Tue, 9 Nov 2004 00:50:26 +0000
To: RDF Data Access Working Group <public-rdf-dawg@w3.org>
Message-ID: <20041109005026.GH15046@login.ecs.soton.ac.uk>

On Mon, Nov 08, 2004 at 02:50:36PM -0000, Andy Seaborne wrote:
> 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
> > 
> All three.  Or just # (c.f. common in scripting languages).

+1 for just #

> > 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.
> And I have replied on IRC and elsewhere.  You don't like the approach of
> allowing different styles of writing; I see that the effect is so small
> on the implementer (and is done in RDLQ) as to not justify picking one.
> Syntax is a value judgement - see other DAWG syntax issues.

My (admittedly small) experience is that having multiple syntax choices
makes it hard for beginners. I usually write RDQL in fully verbose mode
(a, b, c), (a, b, d) etc. and users who started with my examples tend to
get a bit stumped when they see the compact form.

> > 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.
> This is slipping into language design by syntax: I think that rejecting
> a feature (nested optionals) based purely on a minor syntax issue is a
> very bad basis for a decision.

We still need a grouping construct if OR is allowed. I'm not sure that the
syntax is that minor an issue, though I agree that the expressivity -
complexity should have priority.

- Steve
Received on Tuesday, 9 November 2004 00:50:32 UTC

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