- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Thu, 14 Oct 2010 13:10:35 +0100
- To: Axel Polleres <axel.polleres@deri.org>
- CC: Lee Feigenbaum <lee@thefigtrees.net>, SPARQL Working Group <public-rdf-dawg@w3.org>
On 14/10/10 12:18, Axel Polleres wrote:
...
>> I suggest that a sequence of BINDs is considered as ending one BGP, not
>> having nested BGPs subject to FILTERs.
>>
>> ASK { BIND("foo" AS ?bar) . BIND(2 AS ?two) . FILTER(?two = 2) }
>>
>
> ah, ok, gotcha, so you say all BINDs and FILTERS belong to the same group and will be ordered
> in the sense that first the BINDs are evaluated lexicographically and then the FILTERs.
> that looks fine to me then in principle, it just means that the Subselect rwriting discussed
> in the last call would need to put the FILTERs outside the subselect, right?
I wasn't planning on defining the translation of BIND in to the algebra
using that syntactic form. Instead, I was thinking of going direct
during group pattern translatation whch already gathers up FILTER
(not that there are BGPs in the *syntax* any more because of paths).
However, roughly, if P1 and P2 are constrained appropriately:
{ F1 P1 KW(Expr AS ?Var) P2 F2}
=:=
{ { SELECT * (Expr AS ?Var) { P1 P2 } } F1 F2 }
Andy
>
> cheers,
> Axel
Received on Thursday, 14 October 2010 12:11:14 UTC