public IValue ParseFilter(string code)
        {
            parameterQueue = new ArrayList();
            queries = new Stack();
            tokenizer = new Tokenizer();
            tokenizer.Tokenize(code);

            IValue expression = ParseBooleanExpression();
            return expression;
        }
 private NPathSelectQuery InternalParseSelectQuery(string code, IList parameters)
 {
     tokenizer = new Tokenizer();
     tokenizer.Tokenize(code);
     return Begin();
 }