added event for color changes

libs/core/_locales/core-jsdoc-strings.json

@@ -26,6 +26,9 @@
   "input.Button.wasPressed": "See if the button was pressed again since the last time you checked.",
   "input.ColorSensor.ambientLight": "Get current ambient light value from the color sensor.",
   "input.ColorSensor.color": "Get the current color from the color sensor.",
+  "input.ColorSensor.onColorDetected": "Registers code to run when the given color is detected",
+  "input.ColorSensor.onColorDetected|param|color": "the color to dtect",
+  "input.ColorSensor.onColorDetected|param|handler": "the code to run when detected",
   "input.ColorSensor.reflectedLight": "Get current reflected light value from the color sensor.",
   "input.GyroSensor.angle": "Get the current angle from the gyroscope.",
   "input.GyroSensor.rate": "Get the current rotation rate from the gyroscope.",

libs/core/_locales/core-strings.json

@@ -2,6 +2,14 @@
   "ButtonEvent.Click|block": "click",
   "ButtonEvent.Down|block": "down",
   "ButtonEvent.Up|block": "up",
+  "ColorSensorColor.Black|block": "black",
+  "ColorSensorColor.Blue|block": "blue",
+  "ColorSensorColor.Brown|block": "brown",
+  "ColorSensorColor.Green|block": "green",
+  "ColorSensorColor.None|block": "none",
+  "ColorSensorColor.Red|block": "red",
+  "ColorSensorColor.White|block": "white",
+  "ColorSensorColor.Yellow|block": "yellow",
   "LightsPattern.GreenFlash|block": "Flashing Green",
   "LightsPattern.GreenPulse|block": "Pulsing Green",
   "LightsPattern.Green|block": "Green",
@@ -27,6 +35,7 @@
   "input.Button.wasPressed|block": "%button|was pressed",
   "input.ColorSensor.ambientLight|block": "%color| ambient light",
   "input.ColorSensor.color|block": "%color| color",
+  "input.ColorSensor.onColorDetected|block": "on %sensor|detected %color",
   "input.ColorSensor.reflectedLight|block": "%color| reflected light",
   "input.GyroSensor.angle|block": "%sensor|angle",
   "input.GyroSensor.rate|block": "%sensor|rotation rate",

libs/core/color.ts

@@ -9,13 +9,21 @@ const enum ColorSensorMode {
 }
 
 const enum ColorSensorColor {
+    //% block="none"
     None,
+    //% block="black"
     Black,
+    //% block="blue"
     Blue,
+    //% block="green"
     Green,
+    //% block="yellow"
     Yellow,
+    //% block="red"
     Red,
+    //% block="white"
     White,
+    //% block="brown"
     Brown,
 }
 
@@ -23,8 +31,11 @@ namespace input {
 
     //% fixedInstances
     export class ColorSensor extends internal.UartSensor {
+        polling: boolean;
+
         constructor(port: number) {
             super(port)
+            this.polling = false;
         }
 
         _deviceType() {
@@ -35,6 +46,34 @@ namespace input {
             this._setMode(m)
         }
 
+        _initPolling() {
+            if (!this.polling) {
+                input.internal.unsafePollForChanges(
+                    50, 
+                    () => this.color(),
+                    (prev, curr) => {
+                        control.raiseEvent(this._id, curr);
+                    })    
+            }
+        }
+
+        /**
+         * Registers code to run when the given color is detected
+         * @param color the color to dtect
+         * @param handler the code to run when detected
+         */
+        //% help=input/color/on-color-detected
+        //% block="on %sensor|detected %color"
+        //% blockId=colorOnColorDetected
+        //% parts="colorsensor"
+        //% blockNamespace=input
+        //% weight=100 blockGap=8
+        //% group="Color Sensor"
+        onColorDetected(color: ColorSensorColor, handler: () => void) {
+            this._initPolling();
+            control.onEvent(this._id, <number>color, handler);
+        }
+
         /**
          * Get current ambient light value from the color sensor.
          * @param color the color sensor to query the request