@:autoBuild(ComponentID.run()) interface Component {}

class ComponentID {
   public static function run() {
      var fields = Context.getBuildFields();
      // add static '_component_id' field to the objects static fields
      return fields;
   }
}

class ComponentManager {
   macro public static function getType(T:Expr) {
      // convert T into expressing accessing _component_id
      return macro _getType(T'sid);
   }
   static function _getType(id:Int):ComponentType { .. }
}