Added clock example.

examples/clock.js

@@ -0,0 +1,37 @@
+var NoR = require('../lib/NoR.js')
+
+var clock = new NoR(function(signal, enable){}, function(time){
+  var timeout, enable = this.enable, signal = this.signal
+  tick = function() {
+    signal(! signal() )
+    timeout = setTimeout(tick, time())
+  }
+  enable.subscribe(function(enable){
+    if(enable) {
+      tick()
+    } else if(timeout){
+      clearTimeout(timeout)
+    }
+  })
+})
+
+var counter = new NoR(function(clock, count){
+  count( count() + 1 )
+}, function(){
+  // mark the count cell so it doent
+  // trigger counter execution again
+  // mark it as an outputOnly cell.
+  this.count.isOutput = true
+})
+
+var c = clock(true, false, 300)
+var n = counter(c.signal, 0)
+n.count.subscribe(function(time){
+  console.log("SIGNAL on time", time, c.signal())
+  if(time > 9) {
+    c.enable(false)
+  }
+})
+
+
+c.enable(true)