anchor.diff:  //
   
   program:
  -    PROGRAM_KW name=TID LPAREN params+=formalParam (COMMA params+=formalParam)* RPAREN LBRACKET nls
  +    PROGRAM_KW name=TID LPAREN params+=formalParam (commaNl params+=formalParam)* RPAREN LBRACKET nls
       (statements += statement)*
       RBRACKET nls;
   
  
positive.code:     ;
  
  invokation:
      function=basicExpression LPAREN (params+=actualParam (COMMA params+=actualParam)*)?  RPAREN ;
  
  fieldAccess:
      subject=basicExpression POINT name=ID;
  
negative.code:     INT;
  
  creation:
      (pakage=qualifiedId POINT)? name=TID LPAREN (params+=actualParam (commaNl params+=actualParam)*)?  RPAREN ;
  
  varDecl :
      VAL_KW (type=typeUsage)? name=ID ASSIGNMENT value=expression nls;
  