[rules-users] MVEL expression

[Mark Proctor]

Mark Proctor wrote:
> Femke De Backere wrote:
>> Another question ;), 
>>
>> Can I perform a cast in MVEL? eg. Patient((ShortSedation) 
>> sedation.sedation24 == *false*)
> the LHS "when" is not MVEL, it's DRL Pattern language, it's just that 
> some things we translate to MVEL for execution. Our pattner language 
> does not support casting, no. However MVEL itself does support 
> casting, and you can do that on a RHS "then" which is full MVEL.
Sorry that's not quite true, if you use an EVAL thats pure MVEL a cast 
should work inside of that, as evals are like black boxes to the rule 
engine and they are executed directly by java or mvel depending on the 
dialect you chose.

Mark
>
> Mark
>>
>> Thx
>>
>> Op 17-mrt-09, om 19:27 heeft Edson Tirelli het volgende geschreven:
>>
>>>
>>>    Although Drools makes extensive usage of MVEL, it is always 
>>> embedded in the DRL language. So, it is Drools that defines that a 
>>> field constraint is always a field accessor in the left with one or 
>>> more restrictions in the right.
>>>
>>>    We need to find a way to make the Drools x MVEL relationship more 
>>> clear because it is not the first time this slight confusion is made. 
>>>
>>>    Anyway, docs are being updated, but take a look at the Pattern 
>>> documentation (item 7.8.2.1):
>>>
>>> https://hudson.jboss.org/hudson/job/drools/lastSuccessfulBuild/artifact/trunk/target/docs/drools-expert/html/ch07.html#RuleLanguage-ConditionalElements
>>>
>>>    []s
>>>    Edson
>>>
>>>
>>>
>>> 2009/3/17 Femke De Backere <femmyke at gmail.com 
>>> <mailto:femmyke at gmail.com>>
>>>
>>>     Thx!
>>>
>>>     Do you know where I could find a tutorial of MVEL in Drools,
>>>     because I looked at some MVEL tutorials yesterday and I didn't
>>>     find the solution...
>>>
>>>     2009/3/17 Edson Tirelli <tirelli at post.com
>>>     <mailto:tirelli at post.com>>
>>>
>>>
>>>            Left side of a constraint should always be a field
>>>         name... no expression allowed. Either move the expression to
>>>         the right side or use eval.
>>>
>>>         Patient( sedation.ultiva > ( 0.1 - 0.02 ) )
>>>
>>>            Or even better:
>>>
>>>         Patient(sedation.ultiva > 0.08)
>>>
>>>            []s
>>>            Edson
>>>
>>>         2009/3/16 Femke De Backere <femmyke at gmail.com
>>>         <mailto:femmyke at gmail.com>>
>>>
>>>             Hi,
>>>
>>>             The following expression keeps returning the
>>>             error [112,32]: [ERR 103] Line 112:32 no viable
>>>             alternative at input '+' in rule
>>>             "RuleFlow-Split-masterproef.ruleflows.shortsedation-18-22"
>>>             in pattern Patient:
>>>             Patient(sedation.ultiva+0.02 > 0.1)
>>>             with sedation.ultiva returning a double
>>>             What am I doing wrong?
>>>             Thx,
>>>             Femke
>>>
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>>>
>>>
>>>
>>>
>>>         -- 
>>>          Edson Tirelli
>>>          JBoss Drools Core Development
>>>          JBoss, a division of Red Hat @ www.jboss.com
>>>         <http://www.jboss.com>
>>>
>>>         _______________________________________________
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>>>         https://lists.jboss.org/mailman/listinfo/rules-users
>>>
>>>
>>>
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>>>
>>>
>>>
>>> -- 
>>>  Edson Tirelli
>>>  JBoss Drools Core Development
>>>  JBoss, a division of Red Hat @ www.jboss.com <http://www.jboss.com>
>>> _______________________________________________
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>>
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