Re: [TED] CORE Pages on Positive Conditions and Horn Rules Edited: Slots & Constraints

Dave Reynolds <der@hplb.hpl.hp.com> wrote:
> 
> Boley, Harold wrote:
> > Referring to the slides of an F2F4 breakout session
> > (http://lists.w3.org/Archives/Public/public-rif-wg/2006Nov/0025.html),
> > I edited two wiki pages for extending the existing work with
> > slots and calls to external constraint solvers (ACTION-180):
> 
> Thanks. I'm not sure I properly understood the results from the breakout 
> session so forgive me if these questions are off base ...
> 
> > Slots (CORE Page on Positive Conditions):
> > 
> > http://www.w3.org/2005/rules/wg/wiki/A.1_Basis%3A_Positive_Conditions
> > 
> > http://www.w3.org/2005/rules/wg/wiki/A.1_Basis%3A_Positive_Conditions?ac
> > tion=diff&rev2=45&rev1=43
> 
> That just seems to add slotted notation in as an additional piece of 
> syntax. For some reason I'd had the impression that the proposal was 
> that the slotted notation would be the fundamental one with labels '1', 
> '2' etc used to translate positional notation. I guess I expected the 
> revised abstract syntax to only have slotted notation and there would be 
> a separate "with syntactic sugar" syntax layered on top.

It seems that you and Chris understood things quite differently :-)

Note that both syntaxes are syntactic sugars of each other.
What we had in mind (and I hope Hasan, too) that the syntax will allow
users to choose what they want.

Your remark above regarding ``a separate "with syntactic sugar" syntax
layered on top'' seems to be suggesting the same. The only difference is
whether the syntactic sugar will be at the very first layer or at the next one.
Personally, I don't see a reason to have an extra layer for that.


> Note, it's not that I'm necessarily trying to push for this just trying 
> to understand at this stage.
> 
> > Calls to external constraint solvers (CORE Page on Horn Rules):
> > 
> > http://www.w3.org/2005/rules/wg/wiki/B.1_Horn_Rules
> > 
> > http://www.w3.org/2005/rules/wg/wiki/B.1_Horn_Rules?action=diff&rev2=24&
> > rev1=22
> 
> First, I guess I have the same question as above. This seems to have 
> EXTCALL added as an optional extra call whereas I thought the proposed 
> most primitive form of RIF Core was slotted notation with a conjunction 
> of ground dot-notation terms in the constraint equation.

No, dotted notation was just an explanation of how slotted (and nonslotted)
notation can be encoded with a single function symbol (a dot). There is no
need to expose such a low-level detail to the user.

> Second, and related, presumably there needs to be an abstract syntax for 
> the primitive constraint equations needed for Herbrand terms?

Yes, you are right. As far as I remember, we agreed to have only equalities
in the nucleus (and this should be in the BNF). Later we are to decide what
other constraints to add (e.g., over rational numbers, time, etc.) to the
core.




	--michael

Received on Tuesday, 21 November 2006 12:49:16 UTC