Using annotations

Dart shares with other languages such as Java and C# the ability to attach (or annotate) variables, classes, functions, methods, and other Dart program structures with metadata words preceded by an @ sign. This is done to give more information about the structure, or indicate that it has a special characteristic or behavior. Examples are @override, @deprecated, and @observable (used in Polymer), so they are liberally used by the Dart team. Also, Angular.dart uses them abundantly. Moreover, you can also define your own annotations.

How to do it...

In the project annotations, we gave our Embrace class the metadata @ToFix. The strangle method is denoted by @deprecated, and we indicate with @override in Embrace that we want to override the method consumedCalories inherited from Movement, as shown in the following code:

const Anno = "Meta";

void main() {
  var embr = new Embrace(5);
  print(embr);
  var str = new Embrace. strangle();
}

@Anno
@ToFix("Improve the algorithms", ...