CLIPS - Adding the slots of two facts

Question

I am fairly new to CLIPS , been trying to implement a program , based on a lecture , that adds the values of 2 slots , of two facts respectively. I begin with defining the templates of o1 , o2 (the two facts that we add) and o3 (where we store the result) . Each of the first two facts , o1 and o2 , have 2 slots , s1 and s2 . The slots of o3 are r1 and r2 . Then I proceed to initialize the slots o1 and o2 , using deffacts . Then , ending , using defrule , I set variables to the slots of o1 and o2 and using assert to generate the o3 fact , which slots r1 will have the sum of values of the first slot of the facts o1 and o2 , and r2 will the sum of the second . I'm using ubuntu , loading the clp clips file with clips -f try.clp command , and then executing (run) and at last , (facts) , but can't see the new facts , or either of the pre-existing ones . Can someone guide me with this ? I'm posting my code and screenshot of running the program.

Here is my code :

(deftemplate o1
    (slot s1) 
    (slot s2))

(deftemplate o2
    (slot s1) 
    (slot s2)) 

(deftemplate o3
    (slot r1)
    (slot r2))

; Facts
(deffacts F 
    (o1 (s1 3)(s2 5))
    (o2 (s1 7)(s2 9)))


; Rules
(defrule R 
    (o1 (s1 ?x1)(s2 ?y1))
    (o2 (s1 ?x2)(s2 ?y2))
=>
    (assert (o3(r1 (+ ?x1 ?x2))(r2 (+ ?y1 ?y2))))
)

and screenshot with running the program :

Answer 1

You need to issue a (reset) command before your (run) command. Reset removes all existing facts and then asserts the facts specified in your deffacts.