[rules-users] JBoss Drools evaluation

[Wolfgang Laun]

On 08/07/2013, Mark Proctor <mproctor at codehaus.org> wrote:
>
> On 8 Jul 2013, at 08:03, Wolfgang Laun <wolfgang.laun at gmail.com> wrote:
>> Some backward chaining functionality is indeed available, although it
>> cannot be compared with what you have in, say, Prolog.
> that might be an undersell. We do full derivation tree's, as per prolog. But
> we take this a step further, and have fully reactive derivation trees -
> which most prolog systems does not have.
> http://www.youtube.com/watch?v=fCjIRVSRFvA
>
> The prolog features we do not have are:
> cut
> List unification.
> Unbound properties  for fact instances. So that it unifies against the
> property.
> Expressions for arguments in unifications.
>

What about arithmetic? Is this what you mean with the last item, e.g.
  fact(0,1).
  fact(N,R):- fact(N1,R1),N is N1+1,R is R1*N.

It's OK to expect a hybrid system to have facets not present in one or
the other "pure" system. There's a considerable number of exercises
you can do in Prolog, but can't do in Drools  - and the other way
round, to be sure!