Additional Xbase features

In this section, we will show a few additional Xbase features, and we will apply them to the Xbase Entities DSL we implemented so far.

Annotations

Xbase provides support for Java-like annotations. This support is not enabled in the standard Xbase grammar. If you want to use Xbase annotations in your DSL, then you must use org.eclipse.xtext.xbase.annotations.XbaseWithAnnotations as the super grammar:

grammar org.example.xbase.entities.Entities
  with org.eclipse.xtext.xbase.annotations.XbaseWithAnnotations

Now, you can use the Xbase grammar rules for annotations. In this example, we will add annotations to entities and attributes:

Entity:
annotations+=XAnnotation*
'entity' name=ID ('extends' superType=JvmParameterizedTypeReference)? '{'
    attributes += Attribute*
    operations += Operation*
'}';

Attribute:
  annotations+=XAnnotation*
  'attr' (type=JvmTypeReference)? name=ID
  ('=' initexpression=XExpression...