Re: [dotNetRDF-Develop] Integrating SPIN into dotnetrdf

[Rob V. <rv...@do...>]

Hey Kevin

Discussion inline:

From:  Kevin <ke...@th...>
Date:  Wednesday, March 13, 2013 7:40 PM
To:  Rob Vesse <rv...@do...>
Subject:  Integrating SPIN into dotnetrdf

> Rob,
>  
> First thank you for your quality work you have done with the dotnetrdf
> project.  I have seen a few different posts about your initiative to integrate
> SPIN into dotnetrdf (ie.  SPIN Post
> <http://answers.semanticweb.com/questions/537/experiences-with-spin> ).  After
> much reading on the subject it really seems that SPIN would really
> propel/complement dotnetrdf.  I believe SPIN not only makes up for the missing
> OWL inference (Via SPIN OWL-RL implementation), it also can expand to suit the
> modelers imagination.  The fact that the rules are in SPARQL makes for an
> unbeatable solution.  Should it matter my current effort involves query a
> Virtuoso database (Some owl support) with dotnetrdf.  I would really
> appreciate you taking a look at the questions below:
>  
> -Have you made any further progress on integrating SPIN into dotnetrdf?  Would
> you allow me to have the source code in its current state?  Could I possibly
> be a contributor on this cause as I am not really equipped for the full task?
> In any case I would appreciate any source code which I could use as a learning
> tool.

No I haven't had time to do anything on SPIN for a long time now.  I've been
primarily concentrating on getting core features stabilized such as the
SPARQL engine which are obviously fairly key to building stuff like SPIN on
top.

However I still don't have time to work on SPIN directly so if you want to
work on this please feel free, find the code in the mercurial repository at
https://bitbucket.org/dotnetrdf/dotnetrdf

The previous and very minimal SPIN stub is under Libraries\Query\Spin,
create your own fork and then you can send pull requests as and when you
have something to 

The key things that need to be done to get the core of SPIN implemented are
as follows:
* Update the current spin-sparql-syntax.ttl to a current version, it likely
doesn't represent the current version of the spec (this is primarily a
convenience reference for developers)
* Finish the existing stubs for converting queries into their SPIN RDF
representation (see SpinSyntax.cs)
* Write code to turn a RDF encoding of a SPIN query into a query
The middle one would be the easiest to start with since there is already
some partial stubs to get you started.

>  
> -From the available TopQuadrant documentation I have tried to deduce how
> dotnetrdf might implement SPIN.  According to SPIN tutrial
> <http://dallemang.typepad.com/my_weblog/2010/08/extending-owl-rl-.html> ,
> TopBraid finds all SPIN inferecer rules and runs them when you hit play.
> Would dotnetrdf SPIN inferencer only run the rules that are associated with
> the class structure being queried?  Basically I am confused how dotnetrdf
> decides when/how/which SPIN rules to run for a given query.

That's an implementation detail, we would control how and when rules get
run.  We need to get the basic implementation of SPIN done first before this
aspect of things gets implemented anyway.

>  
> -How much of SPIN could dotnetrdf possibly support.? It appears SPIN contains
> Inference Rules, Constraint Checking, and ability to Isolate rules for certain
> conditions.  Also the TopBraid tool seems to have  "User-Defined SPARQL
> functions" and "SPIN Query Templates".  I imagine dotnetrdf would have to keep
> up with any SPIN improvements.

All of those are supportable in some shape of form, until we have the core
of SPIN up and running we can't really implement those.  Most of those
features run on top of the SPIN core and so will ultimately just be
implementation details once we have a core to build upon.  User defined
SPARQL functions are basically just SPARQL queries that return a single
value and query templates are just parameterized queries both of which the
existing SPARQL engine is capable of supporting in one way or another.  So
it is just a case of exposing that functionality in the SPIN style.

Hope this is enough to get you started, if not please let us know,

Rob

>  
> Regards,
> Kevin