Are you trying to see if a person meets multiple requirements? Here's how:


(defrel grade person course g)
(fact grade 'Bob 'Algebra 'B) 
(fact grade 'Bob 'Art 'C) 
(fact grade 'John 'Algebra 'A) 
(fact grade 'John 'Art 'A) 
(fact grade 'Ricky 'Algebra 'D) 
(fact grade 'Ricky 'Art 'A)

(defn meets-requirements [person [k & nowledge]]
  (if-let [{:keys [course g]} k]
    (all
     (grade person course g)
     (meets-requirements person nowledge))
    succeed))


#_ (run* [person]
     (meets-requirements
      person
      [{:course 'Algebra :g 'B}
       {:course 'Art :g 'C}]))


On Saturday, 19 May 2012 15:07:47 UTC-4, Alex Robbins wrote:
>
> Hmm, I didn't explain it very well. What if I had more knowledge? 
> Maybe I knew two grades sometimes. That could cut down on the list of 
> possible students (assuming there are more than the three in my 
> example). 
>
> How could I write a function that worked for both of these cases? 
> (matches [{:course 'Algebra :g 'B}]) 
> (matches [{:course 'Algebra :g 'B} {:course 'Art :g 'C}]) 
>
>
> On Sat, May 19, 2012 at 2:02 PM, David Nolen <dnolen.li...@gmail.com> 
> wrote: 
> > I don't think you need to generate goals for something as 
> straightforward as 
> > this: 
> > 
> > (defrel grade person course g) 
> > (fact grade 'Bob 'Algebra 'B) 
> > (fact grade 'Bob 'Art 'C) 
> > (fact grade 'John 'Algebra 'A) 
> > (fact grade 'John 'Art 'A) 
> > (fact grade 'Ricky 'Algebra 'D) 
> > (fact grade 'Ricky 'Art 'A) 
> > 
> > (defn matches [{:keys [course g]}] 
> >   (run* [q] 
> >     (fresh [p] 
> >       (grade p course g) 
> >       (== q [p course g])))) 
> > 
> > (matches {:course 'Algebra :g 'B}) 
> > 
> > On Sat, May 19, 2012 at 2:12 PM, Alex Robbins 
> > <alexander.j.robb...@gmail.com> wrote: 
> >> 
> >> I'm just getting started with logic programming, and it is entirely 
> >> possible I'm just approaching this incorrectly. 
> >> 
> >> Is it possible to use dynamically generated goals in run* ? 
> >> 
> >> For example, 
> >> 
> >> (defrel grade person course g) 
> >> (fact grade 'Bob 'Algebra 'B) 
> >> (fact grade 'Bob 'Art 'C) 
> >> (fact grade 'John 'Algebra 'A) 
> >> (fact grade 'John 'Art 'A) 
> >> (fact grade 'Ricky 'Algebra 'D) 
> >> (fact grade 'Ricky 'Art 'A) 
> >> 
> >> (def knowledge 
> >>  {:course 'Algebra :g 'B}) 
> >> 
> >> (defn generate-goals [knowledge] 
> >>  (map 
> >>    (fn [{:keys [course g]}] (list 'grade 'person course g)) 
> >>    knowledge)) 
> >> 
> >> I want to do something like this (but valid clojure): 
> >> (run* [person] 
> >>  ~@(generate-goals knowledge)) 
> >> 
> >> It should give me back a list of people who match my current 
> >> knowledge. If I have more knowledge about the person, it will generate 
> >> more conditions, less knowledge fewer conditions. However, since run* 
> >> and run are macros, I can't apply them to a list. I can't splice in 
> >> because I'm not in a quotes list. Any ideas? 
> >> 
> >> Thanks! 
> >> 
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