Re: [rules-users] using complex evaluate expressions with DSL

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(a)gmail.com&gt; 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(a)gmail.com&gt; > >> 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(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/rules-users >> >> > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > >