TRUE
CLIPS> (batch "exists.bat")
TRUE
CLIPS> (clear)      ; Test exists
CLIPS> (watch activations)
CLIPS> (watch facts)
CLIPS> 
(defrule test
   (exists (a ?))
   =>)
CLIPS> (reset)
CLIPS> (assert (a 1))
==> f-1     (a 1)
==> Activation 0      test: *
<Fact-1>
CLIPS> (assert (a 2))
==> f-2     (a 2)
<Fact-2>
CLIPS> (assert (a 3))
==> f-3     (a 3)
<Fact-3>
CLIPS> (retract 1)
<== f-1     (a 1)
CLIPS> (retract 3)
<== f-3     (a 3)
CLIPS> (retract 2)
<== f-2     (a 2)
<== Activation 0      test: *
CLIPS> (assert (a 4))
==> f-4     (a 4)
==> Activation 0      test: *
<Fact-4>
CLIPS> (clear)
CLIPS> 
(defrule test
   (a ?x)
   (exists (b ?x ?))
   =>)
CLIPS> (reset)
CLIPS> (assert (b 1 1))
==> f-1     (b 1 1)
<Fact-1>
CLIPS> (assert (b 1 2))
==> f-2     (b 1 2)
<Fact-2>
CLIPS> (assert (a 1))
==> f-3     (a 1)
==> Activation 0      test: f-3,*
<Fact-3>
CLIPS> (assert (a 2))
==> f-4     (a 2)
<Fact-4>
CLIPS> (retract 1)
<== f-1     (b 1 1)
CLIPS> (retract 2)
<== f-2     (b 1 2)
<== Activation 0      test: f-3,*
CLIPS> (assert (b 2 2))
==> f-5     (b 2 2)
==> Activation 0      test: f-4,*
<Fact-5>
CLIPS> (assert (b 1 2))
==> f-6     (b 1 2)
==> Activation 0      test: f-3,*
<Fact-6>
CLIPS> (assert (b 2 3))
==> f-7     (b 2 3)
<Fact-7>
CLIPS> (assert (b 1 3))
==> f-8     (b 1 3)
<Fact-8>
CLIPS> (retract 7)
<== f-7     (b 2 3)
CLIPS> (retract 5)
<== f-5     (b 2 2)
<== Activation 0      test: f-4,*
CLIPS> (retract 3)
<== f-3     (a 1)
<== Activation 0      test: f-3,*
CLIPS> (unwatch facts)
CLIPS> (unwatch activations)
CLIPS> (clear)
CLIPS> (defrule foo (a) (exists (a) (a)) =>)
CLIPS> (reset)
CLIPS> (assert (a))
<Fact-1>
CLIPS> (agenda)
0      foo: f-1,*
For a total of 1 activation.
CLIPS> (retract 1)
CLIPS> (agenda)
CLIPS> (clear) ; 6.3 Issue
CLIPS> (unwatch all)   
CLIPS> 
(defrule detect
   (b ?b)
   (exists (a))
   (test (eq ?b 2))
   =>
   (printout t "Rule Fired" crlf))
CLIPS> (assert (a))
<Fact-1>
CLIPS> (assert (b 1))
<Fact-2>
CLIPS> (run)
CLIPS> (reset)
CLIPS> (assert (b 1))
<Fact-1>
CLIPS> (assert (a))
<Fact-2>
CLIPS> (run)
CLIPS> (reset)
CLIPS> (assert (a))
<Fact-1>
CLIPS> (assert (b 2))
<Fact-2>
CLIPS> (run)
Rule Fired
CLIPS> (reset)
CLIPS> (assert (b 2))
<Fact-1>
CLIPS> (assert (a))
<Fact-2>
CLIPS> (run)
Rule Fired
CLIPS> (clear) ; 6.3 Issue
CLIPS> 
(deffacts xy
    (SAD T 1 T07 "12345678"))
CLIPS> 
(defrule x
   (exists (SAD T ?ix T07 ?str)
       (test (>= (str-length ?str) 0))) 
   (test (=  1 1))
   =>)
CLIPS> (reset)
CLIPS> (agenda)
0      x: *
For a total of 1 activation.
CLIPS> (clear)
CLIPS> (dribble-off)