Re: [rules-dev] Constraint efficiency: (was: "New in 5.2.0" - What works, what doesn't?)

Edson, On 6 May 2011 01:14, Edson Tirelli <ed.tirelli(a)gmail.com <mailto:ed.tirelli@gmail.com>> wrote: Wolfgang, These are remaining bugs that must be fixed before final. Goal is to support free form expressions as long as they return a boolean value (for traditional constraints), or any value (for positional). Period. (Well, as it's past 5.2.0M2...) Given that any expression is valid, will there still be a distinction w.r.t. efficiency, as there was with traditional constraints as opposed to eval()? If yes, how can I tell whether a constraint expression is "good" or "bad"?

One might assume that all legacy forms will be handled as efficiently as now, but it's possible that not only field == ($var + 1) but also field == $var + 1 is efficient. Or, similarly, field == $var and (now) also $var == field But certainly not field - 1 == $var Or, at least, not until some later version ;-) I repeat this quote (from 5.2.0Drools Introduction and General User Guide) and my question, what does it mean? Where is this "documented"? Is this somehow related to the efficiency issue? <quote> As previously we had to document the restricted limitations of a field constraint on the LHS compared to expressions used inside of an 'eval' or used on the RHS. </quote> Wolfgang Edson 2011/5/5 Wolfgang Laun <wolfgang.laun(a)gmail.com <mailto:wolfgang.laun@gmail.com>> In the 5.2.0 Drools Introduction and General User Guide, there's section 2.1.3.1, Free Form expressions in Constraints (New Parser). It contains several examples: #1 Person( age * 2 > $anotherPersonsAge + 2 ) #2 Person( addresses["home"].streetName.startsWith( "High Park" ) ) #3 Person( isAdult() ) #1 does not compile: Unable to build constraint as 'age * 2' is invalid : [Rule name='exa1'] #2 works - although I'd very much prefer not to be swamped with MVEL extensions unless I ask for it. #3 does not compile: Unable to Analyse Expression isAdult(): [Error: no such identifier: isAdult] [Near : {... isAdult() ....}] Neither rule name nor line number is provided. Would it please be possible to have a precise statement what one /can/ write as a constraint? <quote> As previously we had to document the restricted limitations of a field constraint on the LHS compared to expressions used inside of an 'eval' or used on the RHS. </quote> I'm sorry, but I do not understand the meaning of this sentence. What does it mean, please? Cheers Wolfgang _______________________________________________ rules-dev mailing list rules-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-dev