anchor.diff:  
   compilationUnit
       : (importDeclaration)*
  -      (annotations? toplevelDeclaration)+
  +      (annotations? typeDeclaration)+
         EOF
       ;
       
  -toplevelDeclaration
  +typeDeclaration
       : classDeclaration 
  -    | interfaceDeclaration 
  -    //| converterDeclaration 
  -    //| decoratorDeclaration
  +    | interfaceDeclaration
       | aliasDeclaration
       ;
   
  
positive.code: // enforce the rule that the ... appears at the end of the parapmeter
  // list in a later pass of the compiler.
  formalParameter
      :  annotations? type parameterName 
        ( '->' type parameterName | '..' parameterName )? 
        (specifier | '...')?
      ;
  
negative.code:     ;
  
  assignable 
      : reflectedLiteral
      | expression
      ;
  
  