W3C home > Mailing lists > Public > public-rif-wg@w3.org > July 2008

Re: one thing we forgot

From: Sandro Hawke <sandro@w3.org>
Date: Sat, 05 Jul 2008 14:19:40 -0400
To: kifer@cs.sunysb.edu
Cc: public-rif-wg@w3.org (RIF WG)
Message-ID: <28744.1215281980@ubuhebe>


> You cannot determine a dialect just by its syntax. Examples are: LP
> with stable model semantics and with well-founded semantics. 

In that case, as we've been over before, we just use different NAF
operators (smnaf and wfnaf were Axel's examples).

> Closer to home: BLD and a (syntactically) BLD-like document with F-logic
> semantics. The former does not have inheritance, while the latter does.

I'm not familiar with this difference.   Can you give me a test case?
Two small RIF documents which would have different entailments or
consistency?

My intuition from watching languages evolve over the years is that you
can always add new features to a language without disturbing the
existing syntax.  It's not always as nice for users as a re-design which
changes existing syntax, but since users don't write RIF directly,
that's less of a cost here.

> Designing dialects that can be disambiguated syntactically is going to
> be tough and we don't understand this enough. 

We don't understand any of this perfectly, but we have to keep moving
forward.

> I think Harold's proposal for an optional attribute is a good compromise.

Perhaps.  

Thinking more since my e-mail to Harold, I guess there is one case where
it might be useful -- if the receiver knows the named dialect, it can
detect and abort on errors where the sender didn't conform to the
dialect it claimed to conform to.   But that seems like a small benefit
for the cost and confusion.   It's also a violation of Postel's Law
(which should, perhaps, be violated some times).

(Meanwhile, it's up the the chairs, but I don't see any new information
here, and we already decided at F2F10 not to make any other changes, so
this discussion (as something that goes into BLD now) seems out of
order.  A dialect tag could be proposed as an extension, of course.)

We now return to our previously scheduled weekend.

    -- Sandro
Received on Saturday, 5 July 2008 18:21:33 GMT

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