[rules-users] using complex evaluate expressions with DSL

[Wolfgang Laun]

You have omitted the regular expressions from some of the variable
definitions
in DSL entries:

[when][] {attr:\S+} follows pattern {x:\S+} =
startsWithFunction({attr},{x})

Restore them all, and it's OK.

-W



2011/1/4 maverik j <maverikj348 at gmail.com>

> Here is the complete DSL/DSLR
>
> DSLr:
> rule "Your First Rule"
>
>  when
>     There is a Department
>     There is at least one Person
>     - with a valid subOrdinate
>     - check that name follows pattern "M"
> then
>    >System.out.println("Test Generic Cosntranit done !!!");
> end
>
> DSL:
> [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 {attr} equal to {value} = {attr} == {value}
> [when][]- with a valid {attr} = {attr} != null
>
> [when][]- with {attr} not equal to {value} = {attr} != {value}
> [when][]- eval\( {whatever} \)= eval( {whatever} )
> [when][] {attr} equals {value} = {attr}.equals({value})
> [when][] {attr} is valid  =  {attr} != null
> [when][] {attr} follows pattern {x} =  startsWithFunction({attr},{x})
>
> Function used in drl is:
> function boolean startsWithFunction(String value, String beginning) {
>  if (value == null) return false;
>  if (beginning == null) return false;
>  return value.startsWith(beginning);
> }
> I am using drools version 5.1.1
>
> Thanks & Regards,
> -Maverik
>
> 2011/1/4 Wolfgang Laun <wolfgang.laun at gmail.com>
>
>> Do you have any comments ("#..." or "//...") between when and then? If so,
>> please remove and try again.
>>
>> If this doesn't fix it, please post completely and exactly
>> - the rule from the DSLR
>> - the full DSL
>> - Drools version.
>>
>> Thanks
>> -W
>>
>>
>>
>>
>> 2011/1/4 maverik j <maverikj348 at gmail.com>
>>
>>>
>>>
>>> 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
>>>>>>>>
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>>>>>>>> rules-users at lists.jboss.org
>>>>>>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>>>>>>
>>>>>>>>
>>>>>>>
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>>>>>>>
>>>>>>>
>>>>>>
>>>>>
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