[rules-users] Partial Unification / Derivation of Facts?

[Wolfgang Laun]

This uses several terms I'm not familiar with in this context, but it seems
that

   1. a ule uniquely determines a Class to be instantiated on its RHS
   2. a set of parameters is required that, in turn, depends on the Class
   determined according to (1).

I do not understand why these parameters cannot be inserted as facts.

Each parameter set (!) would be a fact with one field containing the Class,
and this could be matched in the rule, passing parameters to the processing
to be done in the same rule.

      $p: Params( clazz == (FactorType1.class), $pSet: paramSet )

-W


On 27 September 2011 15:11, JohnnyCaimbridge <nbower at nycm.com> wrote:

> NOTE: Reposted because I only just subscribed to the mailing list.
>
> Hello,
>
> I have a set of Fact types which represent factors matched and used
> throughout the other rules.  Each of these Fact types may be derived in a
> variety of mutually exclusive ways--ie based on the line of business or
> other factors.  The rules are all well-defined for these Facts.  Something
> like this:
>
> declare FactorType1
>   value : BigDecimal
> end
>
> rule "FactorType1"
> when
>   LineOfBusiness( this == LineOfBusiness.LOB1 )
>   // some other conditions
>   $prms : Params() // ***provisional*** where to specify needed context
> dependent parameters? see below
> then
>   BigDecimal value = new BigDecimal("0");
>   // ... determine value based on conditions and $prms
>   insert( new FactorType1(value) );
> end
>
> // <some other mutually exclusive rules to derive FactorType1 here>
>
> The problem is that in the rules which match these Facts, there are many
> context dependent (ie *always* unique to that particular rule) parameters
> which must be "passed" to the derivation of those Facts.  I'm referring to
> these as "Params" above.  Now, a rule that uses FactorType1:
>
> rule "a rule that uses FactorType1"
> when
>   // some conditions
>   FactorType1( $value )
>   $prms : Params(prm1,prm2,prm3,...) // ***provisional*** how to indicate
> that FactorType1 should use these parameters in its derivation?
> then
>   // perform some calculation with $value
> end
>
> The parameters which these Facts use cannot be asserted as Facts
> themselves.
> They are unique to the rules which match on the FactorTypes, so that would
> mean I'd need a duplicate rule for every rule that uses a FactorType (even
> with "rule inheritance", this is excessive).
>
> It's almost as if I need to specify a "partial derivation" or "partial
> unification" of the Fact type, which is only asserted once a rule indicates
> that it is providing the "unbound" portion of the derivation.  I understand
> queries can be used for some sort of partial unification, but I have no
> clue
> how to apply them to my problem and I can't find any good examples or
> documentation on their usage/behavior.
>
> Thanks in advance
>
>
>
> --
> View this message in context:
> http://drools.46999.n3.nabble.com/Partial-Unification-Derivation-of-Facts-tp3372546p3372546.html
> Sent from the Drools: User forum mailing list archive at Nabble.com.
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