[rules-users] matching multiple facts in a rule using a DSL template

[Erik Clairiot]

Okey, I should have spend more time with DSL...
I didn't know it was possible to use a matching pattern either for variable
name :

[when] there is "{name}" as {key}={key} : Variable(id == "{name}")

Sorry for unnecessary posting, have a nice day.

Erik

On Tue, 28 Jul 2009 17:43:04 +0200, Erik Clairiot <erik at clairiot.com>
wrote:
> Hello,
> 
> I recently started to use DSL template within my rules.
> In the LHS, I oftenly match conditions against multiple facts, facts that
I
> want to modify in the RHS.
> 
> example :
> 
> when
>   $v1 : Variable(id == "A")
>   $v2 : Variable(id == "B")
> then
>   $v1.setFoo();
> end
> 
> If I write a dsl template like that :
> 
> [when] there is "{id}"=v:Variable(id == "{id}")
> [then] foo me=v.setFoo();
> 
> and a dsl rule like that
> 
> when
>   there is "A"
>   there is "B"
> then
>   foo me
> end
> 
> the execution will produce the error "Duplicate declaration for variable
> ..."
> 
> I understand why it occurs.
> 
> how to specify a constraint upon the fact matched ? Dunno if it is
> possible, my opinion will be to create another dsl rule, that is supposed
> to match with the "foo me", but it does not seem to be very convenient.
> 
> Is there a way to use an array for variable assignement in the RHS ? like
> 
> [when] there is "{id}"=v[]:Variable(id == "{id}")
> [then] foo me=v[].setFoo();
> 
> and use it in the RHS of the rule like
> 
> when
>   there is "A"
>   there is "B"
> then
>  foo me [0] // will cause foo me on the first matched fact
> end
> 
> There are a lot of chances this does not exist, and works like that,
maybe
> I am not using DSL well and it is bad idea to match multiple fact with
the
> same dsl template.
> 
> Can someone help me on that ? It is just a question, I am not stuck on
> this, but interested on how to deal with that.
> 
> Thanks.
> 
> Erik
> 
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