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

So I take it that all of these permit indexing: <fieldname> == <literal>

<fieldname> == <variable>

<fieldname> == <qualified-identifier>

<fieldname> == <expression> # not necessarily parenthesized any more!

as well as the same using "!=".

But the following does not permit indexing: <any RHS expression from above> == <fieldname>

Correct? -W On 9 May 2011 03:55, Mark Proctor <mproctor(a)codehaus.org <mailto:mproctor@codehaus.org>> wrote: On 06/05/2011 07:14, Wolfgang Laun wrote: > 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"? Only expressions that are equality constraints on direct fields are currently indexed. Mark > > 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 <mailto:rules-dev@lists.jboss.org> > https://lists.jboss.org/mailman/listinfo/rules-dev _______________________________________________ rules-dev mailing list rules-dev(a)lists.jboss.org <mailto:rules-dev@lists.jboss.org> https://lists.jboss.org/mailman/listinfo/rules-dev _______________________________________________ rules-dev mailing list rules-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-dev