anchor.diff:  
   stringLiteral
       :   STRING
  -    |   { NotifyErrorListeners(reserved_char); } ILLEGAL_STRING
  +    |   { NotifyErrorListeners(errReservedChar); } ILLEGAL_STRING
       ;
   
   // Variable access. The '$' prefix is optional
  
positive.code:     // by default, parse as a passage (full mode)
      public EVineParseMode ParseMode = EVineParseMode.FULL;
  
      private static readonly string reserved_char =
          "'\u000B' (vertical tabulation) is a reserved character and is not allowed to be used!";
      
      private static readonly string errVarDefReservedKw =
  
negative.code: passage
      :   {ParseMode == EVineParseMode.EXPR}? evalExprMode NL? EOF // active only if we're expr parse mode
      |   block* NL? EOF
      |   { NotifyErrorListeners(errReservedChar); } RESERVED_CHARS 
      //|   { NotifyErrorListeners("Error char"); } ERROR_CHAR
      ;
  
  