Re: [rules-dev] accumulate to acc

On 18 August 2011 19:27, Mark Proctor <mproctor(a)codehaus.org <mailto:mproctor@codehaus.org>> wrote: On 18/08/2011 18:17, Wolfgang Laun wrote: > On 18 August 2011 18:38, Mark Proctor <mproctor(a)codehaus.org > <mailto:mproctor@codehaus.org>> wrote: > > We are looking to tighten up accumulate, using a new keyword to > differentiate. It will use ; for separation, to follow a > similar form to > a 'for' loop. > > acc( CE*; > <func>*; > <guard>? ) > > so something like: > > acc( $o : Order(); > $min : min( $o.value ), > $max : max($o.value); > $min > 100 && $max < 100 ) > > > Given that I can do this today using an eval after the accumulate > CE: What's the big gain, as compared to the nuisance of yet > another CE, with the need to document (which, traditionally, > isn't done so eagerly) and teach and learn and getting it free of > bugs? I find the above looks cleaner and easier to read, the more we can reduce the need for 'eval' the better. It is a common enough use case that I feel it is worth support. Well, a condition that's never true isn't a good use case. Even after repairing it, the example does not tell you /where /the min and max, respectively, are. Apart from determining the exact value of mininimum and maximum (which could easily be added, together with locating the containing Order!) not Order( value <= 100 ) not Order( value >= 200 ) is more descriptive that the rather procedural "for" hidden in the proposed "acc".

Perhaps there are better use case; this one does not convince me. -W Acc is used a lot for CEP use cases and we need a syntax that can compete succinctly with alternative approaches - if we look like a dog dinner, we'll lose out to alternative CEP syntaxes. The separation of the segments using ";" gives a clearer distinction too, and it's 'for' loop like nature should more natural to people new to the engine. Mark > > -W > > > I have wondered if we could use pipes on our functions, to be > able to > pass the results of one function into another - just not sure > how that > will work or look yet. > func(...) in func(...) > func(...) | func(...) > > Mark > > _______________________________________________ > 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 <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