- From: Michael Kifer <kifer@cs.sunysb.edu>
- Date: Fri, 04 Jan 2008 22:18:53 -0500
- To: Christian de Sainte Marie <csma@ilog.fr>
- Cc: "Boley, Harold" <harold.boley@nrc-cnrc.gc.ca>, RIF WG <public-rif-wg@w3.org>
> > Michael Kifer wrote: > > > > [...] Formulas like t[] are also useful. If they are allowed, their > > semantics is that the object t exists (without testing any of its > > properties). > > Hmmm. I wonder how useful it is really. > > In order to check the existence of object t, you have to denote it in > some way: How do you denote an object without either asserting or > checking its existence already in the process (thus removing any need to > check it further)? What does one have to do with the other?? It is like asking, "why is it useful to test that a table is not empty? Shouldn't one first create a table and put tuples into it? > Actually, the only use I found for a formula like t[] is to allow the > retraction of an individual without having to allow retracting TERMs as > well as ATOMICs (in RIF-PRD). But that's a different can of worms... You found a use in what context? In PRD or BLD? In logic programming-style dialects this is undoubtedly useful. --michael > Christian > > >
Received on Saturday, 5 January 2008 03:19:02 UTC