Data commit

Task/Active-object/EchoLisp/active-object-1.l

@@ -0,0 +1,30 @@
+(require 'timer)
+
+;; returns an 'object' : (&lamdba; message [values])
+;; messages : input, output, sample, inspect
+(define (make-active)
+		(let [
+		(t0 #f) (dt 0)
+		(t  0) (Kt 0) ; K(t)
+		(S  0) (K  0)]
+		(lambda (message . args)
+		(case message
+			((output) (// S 2))
+			((input ) (set! K (car args))  (set! t0 #f))
+			((inspect) (printf " Active obj : t0 %v t %v S %v "  t0 t Kt (// S 2 )))
+			((sample)
+					(when (procedure? K)
+;; recved new K : init
+					(unless t0
+						(set! t0  (first args))
+						(set! t 0)
+						(set! Kt (K 0)))
+						
+;; integrate K(t) every time 'sample message is received
+					(set! dt (- (first args) t t0)) ;; compute once K(t)
+					(set! S (+ S (* dt Kt)))
+					(set! t (+ t dt))
+					(set! Kt (K t))
+					(set! S (+ S (* dt Kt)))))
+					
+			    (else (error "active:bad message" message))))))

Task/Active-object/EchoLisp/active-object-2.l

@@ -0,0 +1,19 @@
+(define (experiment)
+	(define (K t) (sin (*  PI t )))
+	(define A (make-active))
+	(define (stop)  (A 'input 0))
+	(define (sample t) (A 'sample (// t 1000)))
+	(define (result) (writeln 'result (A 'output)))
+	
+	(at 2.5 'seconds 'result)
+	(every 10 'sample) ;; integrate every 10 ms
+	
+	(A 'input K)
+	(wait 2000 'stop))
+
+(experiment) →
+    3/7/2015 20:34:18 : result
+    result     0.0002266920372221955
+(experiment)  →
+    3/7/2015 20:34:28 : result
+    result     0.00026510586971023164