Module declarations may also specify their superclass explicitly, use inherited fields in the pattern, and contain an entire class body:

module B ( super.len, String s) extends A; 
 
//is equivalent to (given the previous declaration of A)
class B extends A {
  String s;
  B(float l, String s) {super(l); this.s = s;}
 
  public static class Pattern extends UserDefinedPattern {
    private static void signature(@In @Out Y node,
                                          float a, String b ) {}  
             // Notice how the pattern of B take both a and b as parameters 
  }
}