I want to show my support in keeping Drools a pure rule engine. Let procedural programmers (including myself) change their mindset and get into rules world - to reap the best benefits.
No "else" ! On 4/13/06, Peter Van Weert <[EMAIL PROTECTED]> wrote: > > In the spirit of the production-rules-practical-pattern-cookbook, could > anyone elaborate on why a xorGroup is this powerful? Why and where would > it be used? > > Thanks, > Peter > > Ho, Alan wrote: > > Doh !!! That was one of my favorite features :) > > > > I found the concept of a "xorGroup" is a powerful replacement for the > strategy design pattern. In this case, every consequence is a concrete > strategy. Based on the condition, the rule engine selects one consequence ( > a.k.a a specific strategy) to use. > > > > Regards, > > Alan Ho > > > > -----Original Message----- > > From: Mark Proctor [mailto:[EMAIL PROTECTED] > > Sent: Wednesday, April 12, 2006 11:32 AM > > To: [email protected] > > Subject: Re: [drools-user] How to express conditional logic via DRL - ? > > > > There is no xor-group for 3.0. will be in 3.1 > > > > Mark > > Ho, Alan wrote: > > > >>I vote no on having 'else'. > >> > >>The switch statement is exactly the same as the "xorGroup" concept in > DROOLS (aka mutually exclusive rules). In DROOLs 3, how do you make a set of > rules to be part of an XOR group ? > >> > >>Regards, > >>Alan Ho > >> > >>-----Original Message----- > >>From: Dmitry Goldenberg [mailto:[EMAIL PROTECTED] > >>Sent: Tuesday, April 11, 2006 7:57 AM > >>To: [email protected] > >>Subject: RE: [drools-user] How to express conditional logic via DRL - ? > >> > >>This is actually the reasong I went through- wanting to use Drools as a > script execution framework. Ideally, I'd like to see support for > IF-THEN-ELSE and possibly SWITCH. As of now, I don't see a need for any > other "procedural" constructs but it seems to me that IF-THEN-ELSE would be > an immediate need for our users. It would be nice to have explicit support > for it, rather than a whole chapter in our doc explaining how to achieve it > with multiple rules in a rule-set. > >> > >>Thanks, > >>- Dmitry > >> > >>________________________________ > >> > >>From: Mark Proctor [mailto:[EMAIL PROTECTED] > >>Sent: Tue 4/11/2006 10:46 AM > >>To: [email protected] > >>Subject: Re: [drools-user] How to express conditional logic via DRL - ? > >> > >> > >> > >>Unfortunately I'm finding that many people just cannot adjust to the > declarative and coupletely decoupled nature of a rule engine. The end result > is that Drools is used as a script execution framework. > >> > >>Felipe Piccolini wrote: > >> > >> > >>>Mark, > >>> > >>> I could vote on this, I would vote no to the 'else'. The declarative > >>> thing about rule engines is that: no procedural code. So if you > >>> wanna do an 'else' condition you should re-think your rule and chack > >>> if its well writen. Of course this is just MHO. > >>> > >>> :) > >>> > >>>Tuesday, April 11, 2006, 6:09:22 AM, you wrote: > >>> > >>> > >>> > >>> > >>>>I thought about adding 'else' but I couldn't decide on the best way > >>>>to implement it, as there are several possabilities. Also 'else' is > >>>>not considered declarative, so its a kinda of code smell. I'll llook > >>>>into this again in 3.1 > >>>> > >>>> > >>> > >>> > >>> > >>> > >>>>Mark > >>>>Geoffrey Wiseman wrote: > >>>> > >>>> > >>>> > >>>>>On 4/10/06, Dmitry Goldenberg <[EMAIL PROTECTED]> > wrote: > >>>>> > >>>>> > >>>>> > >>>>> > >>>>>>What is the timeframe for 3.1? Else/else if are very important to > >>>>>>what we're trying to do. > >>>>>> > >>>>>>I can see how I can to the following with the method described by > >>>>>>Geoffrey: > >>>>>> > >>>>>>if (A) then B else if (C) then D endif > >>>>>> > >>>>>>I also want to be able to do the following: > >>>>>> > >>>>>>if (A) then B else D endif > >>>>>> > >>>>>>I imagine that the rule would have to be written as a combo of > >>>>>> > >>>>>>if (A) then B endif > >>>>>>if (!A) then D endif > >>>>>> > >>>>>>so that the conditions are complimentary... > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>> > >>>>>Indeed, yes, that's how you'd handle it. > >>>>> > >>>>>If it does make it into 3.1, that's a good thing in terms of > >>>>>supporting the way people think, talk, and work in other languages, > >>>>>but fundamentally, the same capabilities are there now -- they just > require more typing. > >>>>> > >>>>> - Geoffrey > >>>>>-- > >>>>>Geoffrey Wiseman > >>>>> > >>>>> > >>>>> > >>>>> > >>> > >>>-------------------------- > >>>Felipe Piccolini > >>>[EMAIL PROTECTED] > >>> > >>> > >>> > >>> > >>> > >> > >> > >> > >> > >> > >> > > > > > > > > >
