[rules-users] using complex evaluate expressions with DSL

[maverik j]

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} )
in this case it is getting translated to
exists(Person:Person(subordinate != null , funcToEvalPattern( *eval*( name,
"I" ) ) )
where as I was hoping this to be
exists(Person:Person(subordinate != null , *eval *(funcToEvalPattern( name,
"I" ) ) )

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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