Re: what is LDOM? (was Re: example of recursive shapes)

On 2/12/2015 1:23, Peter F. Patel-Schneider wrote:
> - From your example below it appears that LDOM depends on an extended SPARQL
> engine.   Of course, if you utilize a procedural extension to SPARQL then
> you can do anything computable.

Yes correct. That's how recursion is supported. Note that this does not 
require a fundamental change to SPARQL engines. SPARQL functions are an 
official extension point of the SPARQL spec, and all SPARQL databases 
that I know have added their own functions. If a database claims LDOM 
support then it needs to have some engine algorithm implemented anyway. 
Wrapping this algorithm into a SPARQL function shouldn't be all too 
difficult. Databases that do not natively support LDOM can be used via 
an outside control API such as Jena ARQ (we did something similar in the 
open source SPIN API - basically works on all databases with a Jena or 
Sesame bridge). Also note that AllegroGraph already supports recursively 
called SPIN functions that spawn off a new SPARQL query as part of 
another SPARQL query.

Holger

Received on Wednesday, 11 February 2015 23:46:23 UTC