June 2018 Update

Task/Active-object/Julia/active-object.julia

@@ -0,0 +1,40 @@
+mutable struct Integrator
+    func::Function
+    runningsum::Float64
+    dt::Float64
+    running::Bool
+    function Integrator(f::Function, dt::Float64)
+        this = new()
+        this.func = f
+        this.runningsum = 0.0
+        this.dt = dt
+        this.running = false
+        return this
+    end
+end
+
+function run(integ::Integrator, lastval::Float64 = 0.0)
+    lasttime = time()
+    while integ.running
+        sleep(integ.dt)
+        newtime = time()
+        measuredinterval = newtime - lasttime
+        newval = integ.func(measuredinterval)
+        integ.runningsum += (lastval + newval) * measuredinterval / 2.0
+        lasttime = newtime
+        lastval = newval
+    end
+end
+
+start!(integ::Integrator) = (integ.running = true; @async run(integ))
+stop!(integ) = (integ.running = false)
+f1(t) = sin(2π * t)
+f2(t) = 0.0
+
+it = Integrator(f1, 0.00001)
+start!(it)
+sleep(2.0)
+it.func = f2
+sleep(0.5)
+v2 = it.runningsum
+println("After 2.5 seconds, integrator value was $v2")