anchor.diff:        Expression currExpr, left, right;
   
         switch(currToken.type) {
  -        case TokenType.VAL: 
  +        case TokenType.VAL:
             currExpr = new Number(double.parse(currToken.text));
             break;
           case TokenType.VAR:
  
positive.code: 
  /**
   * The Parser creates a mathematical [Expression] from a given input string.
   * 
   * It uses a [Lexer] to create a RPN token stream and then builds the
   * expression.
   * 
   * Usage example:
   *     Parser p = new Parser();
   *     Expression exp = p.parse("(x^2 + cos(y)) / 3");
  
negative.code:           // The current string is not a number and not a simple keyword, so it has to be a variable or function.
            sb = new StringBuffer(varBuffer);
            if(intBuffer.length > 0) {
              /*
               * The intBuffer contains a string and the current string is a
               * variable or part of a complex keyword, so the value is added
               * to the token stream and the current string is added to the
  