Remarks about the current Draft

Dear colleagues,

 

Congratulations first to the draft editors, Harold and Michael, and all
the members for this milestone.

 

I have a few remarks about the draft.

 

It reads mostly well although there are a few minor points I mentioned
to Harold.

 

The introduction states that the condition language is being defined in
WD1. However, it contains Section 3 that discusses rules. So what is the
scope of WD1? It is quite fundamental actually.

 

One interesting issue arises from p. 3.1.1.2, see Example 3. The Draft
suggests that the two forms with explicit existential quantifier in the
body and without it, are equivalent. If one compares that, for example,
with p. 3.5.5.5 of the JBoss Rules manual
(http://labs.jboss.com/file-access/default/members/jbossrules/freezone/d
ocs/3.0.5/html_single/index.html),  we will see that the Drools engine
will behave differently if the exists condition element is used. In
Example 3a, the fact "reject" may be asserted to the Working Memory
multiple times if, for example, there are many instances of "delivered".
(Actually, in the "equality mode", there could be only one instance of
the same fact, so only one fact "reject" will be asserted). I've had a
discussion with Mark Proctor of JBoss Rules and it is clear that there
are issues here that are related to how the Core RIF is relevant for
production rule systems-he seems to be fairly pessimistic about that
relevance. What I am merely pointing out is that implicit quantifiers
may have to become explicit to be unambiguous.

 

Thanks,

 

Alex Kozlenkov

Advanced Technology Group

 

Office: +44 (0)20 8834 6854

Yahoo! Messenger: alex.kozlenkov

 

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