Add all the A tasks

Task/Accumulator-factory/ActionScript/accumulator-factory.as

@@ -0,0 +1,14 @@
+//Throw an error if a non-number argument is used. (typeof evaluates to
+// "number" for both integers and reals)
+function checkType(obj:Object):void {
+    if(typeof obj != "number")
+	throw new ArgumentError("Expected integer or float argument. Recieved " + typeof obj);
+}
+function accumulator(sum:Object):Function {
+    checkType(sum);
+    return function(n:Object):Object {checkType(n); return sum += n};
+}
+var acc:Function=accumulator(2);
+trace(acc(10));
+trace(acc(4));
+trace(acc("123")); //This causes an ArgumentError to be thrown.