Re: Lee's feature proposal

Paul Gearon wrote:
> On Fri, May 1, 2009 at 10:35 AM, Kendall Clark <kendall@clarkparsia.com> wrote:
>> On Fri, May 1, 2009 at 10:30 AM, Lee Feigenbaum <lee@thefigtrees.net> wrote:
> 
> <snip/>
>> Again, fair enough, but we're roughly treating all the features as
>> equivalently substantive in terms of how much it will take to get them
>> specified, and I don't believe that's really true (nor does anyone
>> else, I should think). Also, negation just strikes me as something we
>> *have* to fix or we'll be embarrassed.
> 
> +1
> 
> This was the very first question I answered about how to use SPARQL,
> and it has persisted as the most common question I see. Also, having a
> syntactic construct for negation makes it easier for optimizers to
> identify a subtraction operation, instead of the more general (and
> slightly slower) filtered join. (Not that it eliminates the role of an
> optimizer here, but it's still a win)

I seem to have been very misunderstood here, so let me reiterate.

1) This is just a proposal, first of all.

2) I agree strongly that the SPARQL community would benefit tremendously 
from negation being simpler.

3) I only left it 'off' my proposal because I thought it was already 
covered by subqueries and potentially by surface syntax. I realize now 
how misleading this was. I'll update the proposal over the weekend to 
make this clearer.

Further, Kendall's point regarding how effort required relates to how 
many features we accept as deliverables is a very good one.

Lee

Received on Friday, 1 May 2009 16:21:46 UTC