Hi Dave,
That is an enormous shame. This is a methodology I've worked with in a different library and it makes a very simple way to instantiate complex structures from tabular structures. For instance consider this pseudo code below, it reads a three column CSV file, then it creates URIs for objects and combines these URIs and attributes in the forward chaining bit. This both loads and denormalizes the serialized object structure back into a graph / tree. [loadable: Load(“/mytable.csv”, ?customerName, ?customerAccount, ?service) makeURI(?custObj, ns:, ?customerAccount ) makeURI(?serviceObj, ns:, ?service) -> (?custObj a ns:CustomerAccount) (?custObj ns:customerName ?customerName) (?custObj ns:customerAccountId, ?customerAccount) (?custObj ns:customerHasService ?serviceObj) (?serviceObj a ns:Service) (?serviceObj ns:serviceId ?service) ] I am sure you can see that this method can be applied to lots of different scenarios and is a very simple way to load bindings and immediately create a graph from those bindings. Do you know of other libraries that might support such operations? Cheers, Richard Sent from Surface Pro From: Dave Reynolds Sent: Monday, March 17, 2014 12:13 PM To: [email protected] On 17/03/14 11:44, Richard Morgan wrote: > Hi Dave, > > Thank you for your response, I'm glad to have my thoughts confirmed. Is it > possible to write my own generators and register them like I have with > builtins? No, sorry. For the forward rule system there's simply no equivalent notion. For the backward rules there is the notion of generators but they aren't designed as an extension point (far from it). > The problem I want to solve isn't the regex example above, its more about > generating bindings so I can feed them into a forward rule and then > instantiate triples as a general pattern. Hard. You can write builtins which assert information directly into the deductions graph which can generate as many triples as you want. That's relatively easy and safe. However, it bypasses all the rule machinery and means that other rules don't see the results and you don't get to instantiate more patterns. It might just be possible to write a builtin which would directly call the rule engine to add a rule firing to the conflict set (RETEEngine.requestRuleFiring) and pass in a series of different manufacturing binding environments to each firing request. However, I've never tried anything like that and prodding the underlying engine mechanics from within a builtin is not guaranteed to be safe! Dave > > Cheers, > > Richard > > > On Mon, Mar 17, 2014 at 9:06 AM, Dave Reynolds > <[email protected]>wrote: > >> On 14/03/14 13:53, Richard Morgan wrote: >> >>> Hi, >>> >>> I would like to extend the base regex function in Jena to provide more >>> than >>> one match result. >>> >> >> I don't think that's possible. >> >> >> For instance I would like the following rule >>> >>> [ myregex("the cat sat on the mat", \"(.at)\", ?token) >>> >>> " -> (<http://a> <http://b> ?token)]"; >>> >>> to return >>> >>> - [http://a, http://b, "cat"] >>> >>> - [http://a, http://b, "sat"] >>> >>> - [http://a, http://b, "mat"] >>> >>> From looking at how BindingEnvironment works I can only return with a >>> single binding per variable. >>> >> >> Correct. >> >> In Jena rules then builtins are only used as essentially filters on rule >> firings, they aren't generators. >> >> In the forward rule case (which is suggested by your notation above) that >> wouldn't make sense anyway - forward rules either fire or they don't, >> there's no backtracking. >> >> In the backward rule case then there is backtracking but the interface for >> builtins doesn't support their use as generators. >> >> Dave >> >> >
