Continuing with the examples

examples/pattern-matcher/README.md

@@ -5,6 +5,8 @@ See `../guile/README` for for an intro on running the guile shell needed
 to run te demos here.
 
 * simple.scm: a basic introduction to pattern matching.
+* gsn.scm: calling arbitrary functions upon a match
+
 * fsm-basic.scm: A simple Finite State Machine demo.
 * fsm-full.scm: A generic finite-state-machine constructor
 * markov-chain.scm: A Markov chain (probabilistic FSM) based on above.

examples/pattern-matcher/gpn.scm

@@ -4,48 +4,59 @@
 
 (load-from-path "utilities.scm")
 
+(define (rand-ok atom)
+	(if (< 0 (random 2))
+		(begin
+			(simple-format #t "Picked ~A\n" (cog-name atom))
+			(stv 1 1) ; return true
+		)
+		(begin
+			(simple-format #t "Did not pick ~A\n" (cog-name atom))
+			(stv 0 1) ; return true
+		)
+	)
+)
+
 (EvaluationLink
 	(PredicateNode "is-a")
 	(ListLink
-		(ConceptNode "Linas")
+		(ConceptNode "Aristotle")
 		(ConceptNode "human")
 	)
 )
 
-(define (say-hello atom)
-	(display "hello!")
-	(newline)
-	(stv 0.5 0.5)
+(EvaluationLink
+	(PredicateNode "is-a")
+	(ListLink
+		(ConceptNode "Pierce")
+		(ConceptNode "human")
+	)
 )
 
 (define find-humans
 	(BindLink
 		(VariableNode "$person")
 		(ImplicationLink
-			(EvaluationLink
-		   	(PredicateNode "is-a")
-   			(ListLink
-					(VariableNode "$person")
-      			(ConceptNode "human")
-   			)
-			)
-			(EvaluationLink
-		   	(GroundedPredicateNode "scm: say-hello")
-   			(ListLink
-					(VariableNode "$person")
-   			)
+			(AndLink
+				(EvaluationLink
+					(PredicateNode "is-a")
+					(ListLink
+						(VariableNode "$person")
+						(ConceptNode "human")
+					)
+				)
+				(EvaluationLink
+					(GroundedPredicateNode "scm: rand-ok")
+					(ListLink
+						(VariableNode "$person")
+					)
+				)
 			)
+			(VariableNode "$person")
 		)
 	)
 )
 
 ; (cog-bind find-humans)
 
-(cog-evaluate!  (EvaluationLink
-      (GroundedPredicateNode "scm: say-hello")
-      (ListLink
-         (ConceptNode "Linas")
-      )
-   )
-)