[rules-users] using complex evaluate expressions with DSL

[maverik j]

2011/1/4 Wolfgang Laun <wolfgang.laun at gmail.com>

>
>
> 2011/1/4 maverik j <maverikj348 at gmail.com>
>
>  is there any restriction in terms of using custom function in condition
>> etc.
>> If I add function evaluation to conditions its messing up with dsl. For
>> pattern matching if I use custom function defined in drl then its not able
>> to parse that properly
>>
>> [when][] {attr:\S+} follows pattern {pattern:\S+} =
>> funcToEvalPattern({attr},( {pattern} )
>>
>
> Is this exactly what you have in the DSL definition? It's syntactically
> incorrect.
>


>   Sorry for that, it is actually
>


>  [when][] {*attr*} follows pattern {pattern} = startsWithFunction( {*attr*},
> {pattern} )
>>
>>  and is being added as last statement in DSL (for testing purpose I am
>> using same dsl as you have shown)
>>
>

>   in this case it is getting translated to
>> exists(Person:Person(subordinate != null , startsWithFunction( *eval*(
>> name, "I" ) ) )
>> where as I was hoping this to be
>> exists(Person:Person(subordinate != null , *eval *(startsWithFunction(
>> name, "I" ) ) )
>>
>>
>
> I cannot reproduce this. But it may depend on the order of your entries in
> you DSL file.
>
> Actually I tried changing order as well but didnt worked. I have actually
defined these common functions in drl and added that to knowledgebase along
with these DSL and DSLR.



>  -W
>
>
>
>> Regards,
>> -Maverik
>>
>> On Tue, Jan 4, 2011 at 12:24 PM, maverik j <maverikj348 at gmail.com> wrote:
>>
>>> cool...this was of great help, I will try this out I think it shoudl
>>> solve the purpose.
>>>
>>> Thanks once again,
>>> Maverik
>>>
>>> 2011/1/3 Wolfgang Laun <wolfgang.laun at gmail.com>
>>>
>>> Try using eval as a last resort. A better (smaller, more robust) DSL can
>>>> be designed around facts and their attributes.
>>>>
>>>> "||" (and "OR") can be used, but setting parentheses in order to get the
>>>> priority right is difficult. In constraints, you may have to resort to
>>>> "memberof" or "not memberof".
>>>>
>>>> Your sample isn't self-contained. But I think that the following DSL and
>>>> the DSLR might give you some ideas how to proceed.
>>>>
>>>> [keyword][]check that {conditions}= eval( {conditions} )
>>>> [keyword][]AND = &&
>>>> [keyword][]OR  = ||
>>>>
>>>> [when][][Tt]here is an? {entity}= {entity}: {entity}()
>>>> [when][][Tt]here is at least one {entity}= exists {entity}: {entity}()
>>>>
>>>> [when][]the {entity:\w+}'s {attr:\w+} = {entity}.get{attr}()
>>>>
>>>> [when][]- with a valid {attr} = {attr}: {attr} != null
>>>> [when][]- with {attr} not equal to {value} = {attr} != {value}
>>>> [when][]- eval\( {whatever} \)=eval( {whatever} )
>>>>
>>>> [when][] {attr:\S+} follows pattern {pattern:\S+} =  {attr}.matches(
>>>> {pattern} )
>>>> [when][] {attr:\S+} not equals? {value:\S+} = ! {attr}.equals( {value} )
>>>> [when][] {attr:\S+} is valid  =  {attr} != null
>>>>
>>>> rule "Rule 5"
>>>> when
>>>>     There is a Department
>>>>     There is at least one Person
>>>>     - with name not equal to "xxx"
>>>>     - with a valid subordinate
>>>>     - check that the Person's Id is valid AND the Department's Id
>>>> follows pattern "I" AND the Department's HeadOfDpt not equal name
>>>> then
>>>> end
>>>>
>>>> Notice that "-check that..." must be written as a single line.
>>>>
>>>> -W
>>>>
>>>>
>>>>
>>>>
>>>> 2011/1/3 maverik j <maverikj348 at gmail.com>
>>>>
>>>>>   Hi,
>>>>>
>>>>>  We are planning to use DSL/DSRL approach with generic DSL template
>>>>> like say
>>>>>
>>>>> [condition][]The {object} has valid {field}={object}({field} != null )
>>>>>
>>>>> [condition][]there is object {*obj*} that = {*obj*}()
>>>>>
>>>>> [condition][]- has {*attr*} equal {*val*} = {*attr*} == {*val*}
>>>>>
>>>>> [condition][]- has valid {*attr*} = {*attr*} != null
>>>>>
>>>>> [condition][]- and has {*attr*} equal {value}= && {*attr*} == {value}
>>>>>
>>>>> But there are quite few of requirements like to have DSL rules that can
>>>>> generate expression as follows:
>>>>> exists Employee(
>>>>>    attribute name not equals "xxx"
>>>>>    && the attribute subOrdinate is not null
>>>>>    && eval(
>>>>>    the attribute $dept.getId() is not null
>>>>>    && attribute $dept.getId() follows pattern "I"
>>>>>    && ( ! (the attribute $dept.getHeadOfDpt() equals name)
>>>>>    )
>>>>> )
>>>>>
>>>>> I am not sure if this is possible with DSL. Using '-' operator we
>>>>> cannot really add '&&', '||' conditions it by-default expands to ','
>>>>> separated and conditions. And wirtting generic rules with and/or is not
>>>>> really dynamic to allow any number of expressions in evaluation.
>>>>>
>>>>> i am struggling to get this run since long time so any help/thoughts on
>>>>> this would be  highly appriciable !!!
>>>>>
>>>>> Thanks & Regards,
>>>>> -Maverik
>>>>>
>>>>> _______________________________________________
>>>>> rules-users mailing list
>>>>> rules-users at lists.jboss.org
>>>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>>>
>>>>>
>>>>
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>>>
>>
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