Re: [PRD] need Assign action

Apropos: we talked about _new (a.k.a. Skolem) for BLD use cases, but never
decided anything. Should we try to put it in for the last call?


On Wed, 18 Jun 2008 09:52:28 -0700
Gary Hallmark <> wrote:

> Adrian Paschke wrote:
> > It can not be simulated by a retract action followed by a new assert,
> > because if PRD has a negation (not) the retract might trigger a production
> > rule transition. But that is not the intended semantics of assign/update.
> >   
> what I meant was to add Assign to the definition of the transition 
> relation ?__RIF-PRD ? /P(W)/ × /L/ × /P(W)/ defined in Section 3.3 of 
> the PRD spec.  Assign would be defined as a single transition, not as 
> pair of (retract, assert) transitions.
> Section 3.3 (and associated syntax section) needs some work in any 
> case.  There is no way to do what OBR calls "assert new", which means to 
> create a new frame with a brand new OID.  The existing PRD assert can 
> only take an existing frame and add a slot to it.
> Also, in OBR and in Jess, Retract would not take a frame argument, but 
> rather would take an OID and would retract all the frames that match 
> that OID.

Received on Wednesday, 18 June 2008 20:11:49 UTC