anchor.diff:  
   expr_cast
     : expr_incdec
  -  | NEG expr_incdec
  -  | MINUS expr_incdec
  +  | NEG^ expr_incdec
  +  | MINUS expr_incdec -> ^(UnaryMinus expr_incdec)
     ;
   
   expr_incdec
  
positive.code:   ;
  
  fact
    : NOT fact
    | expr_instanceof
    ;
  
  
negative.code:   Variable;
    ArrayEnd;
    Index;
    UnaryMinus;
  }
  
  program
  