[rules-users] New to rules engine - help in defining rules

[Jeevan Tambuluri]

Thanks Edson! The rule pattern you suggested works for me. Any such 
pattern to simulate "accumulate" in 3.0.x?

Jeevan

Edson Tirelli wrote:

>
>    Jeevan,
>
>    You are right: the simplest way would be use "forall". 
> Unfortunatelly it is only available in trunk.
>    To do it in 3.0.x you will need either a helper attribute or a 
> helper class. For instance, you may add a "branchLength" attribute to 
> the tree and define 2 rules:
>
> rule "define length"
> when
>     $t : Tree( branchLength == -1 )
>     Branch( mytree == $t, $bl : branch_length )
> then
>     $t.setBranchLength( $bl.intValue() );
>     modify( $t );
> end
>
> rule "check length"
> when
>    $t : Tree( $bl : branchLength != -1 )
>    exists Branch( mytree == $t, branch_length != $bl )
> then
>    // do something because the branch has a different length
> end
>
>   There are several variations but you will need 2 rules to emulate this.
>   Hopefully the new version will be out soon solving this kind of 
> problem.
>
>   []s
>   Edson
>
> Jeevan Tambuluri wrote:
>
>> Hello all,
>>
>> I am looking for a way to define rules for the following problem:
>>
>> class Tree {
>> ...
>> }
>>
>> class Branch {
>>    Tree  mytree;
>>     int     branch_length;
>> ...
>> }
>>
>> Let's say I have a fact called Tree and another fact called Branch. 
>> Brach identifies which tree it belongs to.
>> Now, I want to write a rule to say that all branches in a tree must 
>> be of same length.
>> How do I do this with/without using accumulate or forall?
>>
>> Thanks a lot for any help,
>>
>> J
>>
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>>
>
>