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Re: [PRD] Default conflict resolution strategy (ISSUE-64)

From: Christian de Sainte Marie <csma@ilog.fr>
Date: Tue, 05 Aug 2008 17:18:47 +0200
Message-ID: <48986F57.5080806@ilog.fr>
To: RIF WG <public-rif-wg@w3.org>

Mark Proctor wrote:
> I checked with Gary and clips does not implement any 
> no-loop construct.

No, but it implements a refraction (according to the user's guide for 
version 6.0 that I use for reference):

"A rule is activated if its patterns are matched by
1. a brand new pattern entity that did not exist before, or;
2. a pattern entity that did extist before but was retracted and 
reasserted, i.e. a "clone" of the old pattern entity, and thus now a new 
pattern entity".

This is, as I understand it, exactly the reverse of what Oracle/jess 
does (and closer to what JRules does, at least in the spirit).

> Btw no-loop isn't really related to default conflict resolution 
> strategy. What is the plan there?

As I see it after that discussion, PRD should not have a default 
conflict resolution strategy at all, since everybody seems to have a 
different default strategy.

That is, we should add a way to specify the intended CR strategy 
explicitely, and we might specify a number of "builtin" strategy that 
every implementation must understand and be able to implement.

That is: if there are such strategies that all or most engines can 
implement. I thought that some form of no-repeat (or no-loop), some form 
of random, some form of all at once, some form of recency and some form 
of salience might be common enough that they might be inbuilt.

And we might describe a simple algorithm for combining elementary 
strategies, such as the one that is currently described in PRD, if this 
is something that can be implemented easily by all or most engines.

Cheers,

Christian
Received on Tuesday, 5 August 2008 15:17:37 GMT

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