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RE: [RIF] Reaction to the proposal by Boley, Kifer et al --> ECA vs PR

From: Gerd Wagner <wagnerg@tu-cottbus.de>
Date: Wed, 3 May 2006 22:14:40 +0200
To: "'Vincent, Paul D'" <PaulVincent@fairisaac.com>, "'Alex Kozlenkov'" <alex.kozlenkov@betfair.com>, "'Dave Reynolds'" <der@hplb.hpl.hp.com>
Cc: <public-rif-wg@w3.org>
Message-ID: <003701c66eee$363bfa50$17d52b8d@TMGWAGNER>

> Alex: just some views on ECA from a vendor in this space...

Paul, you mean from a production rule vendor's 
point of view, right :-?
 
> > various events, not just data changed. 
> 
> [PV>] Note that this is (mostly) an execution aspect. If I have an ECA
> rule that occurs on event A, it looks very similar to a PRule with a
> condition of the type "event A occurred".
 
I guess, ECA rule vendors would not agree with your
attempt to neglect the specific semantics of events.

It's not an execution aspect, it's a question of the
right semantics. Normally, "condition" (in the sense 
of "logical condition") means "state condition", where
"state" may refer to the state of a system, or to the
"state of affairs".

Now, an event corresponds to a state change and is
therefore a completely different kind of thing that
cannot be subsumed under the concept of a state condition.
A complex logical condition formula is formed with the 
help of logical connectives, while a complex event 
expression is formed with the help of a different set
of (event composition) operators.

It's true that logical conditions and events are all 
mixed up in production rules. Semantically, this is
a mess (and typically production rules do not have
much support for event composition). But you may 
consider it a strength, making production rules
a versatile programming paradigm (however, without
a clear formal semantics).

-Gerd
Received on Wednesday, 3 May 2006 20:14:31 GMT

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