Root instance & dispatcher run once

haxework/dispath/Dispatcher.hx

@@ -10,8 +10,8 @@ class Dispatcher<L:{}> implements IDispatcher<L> {
     listeners = new ObjectMap<L, Bool>();
   }
 
-  public function addListener(listener:L):Void {
-    listeners.set(listener, true);
+  public function addListener(listener:L, once:Bool = false):Void {
+    listeners.set(listener, once);
   }
 
   public function removeListener(listener:L):Bool {
@@ -25,6 +25,12 @@ class Dispatcher<L:{}> implements IDispatcher<L> {
 
   public function dispatch(caller:L->Void):Void {
     var i:Iterator<L> = listeners.keys();
-    while (i.hasNext()) caller(i.next());
+    var r:Array<L> = [];
+    while (i.hasNext()) {
+      var l = i.next();
+      caller(l);
+      if (listeners.get(l)) r.push(l);
+    };
+    for (l in r) listeners.remove(l);
   }
 }

haxework/dispath/IDispatcher.hx

@@ -6,7 +6,7 @@ interface IDispatcher<L:{}> {
 
   private var listeners(null, null):ObjectMap<L, Bool>;
 
-  public function addListener(listener:L):Void;
+  public function addListener(listener:L, once:Bool = false):Void;
   public function removeListener(listener:L):Bool;
   public function removeAllListeners():Void;
   public function dispatch(caller:L->Void):Void;

haxework/gui/Root.hx

@@ -1,5 +1,6 @@
 package haxework.gui;
 
+import flash.errors.Error;
 import flash.Lib;
 import flash.display.StageAlign;
 import flash.display.StageScaleMode;
@@ -9,9 +10,13 @@ import flash.display.Sprite;
 
 class Root {
 
-  private var view:IView<Sprite>;
+  public static var instance(default, null):Root;
+
+  public var view(default, null):IView<Sprite>;
 
   public function new(view:IView<Sprite>) {
+    if (instance != null) throw new Error("Only one instance");
+    instance = this;
     this.view = view;
     Lib.current.addChild(view.content);
     var content:DisplayObject = view.content;