System.Xml.Xsl.Xslt.QilGenerator.MatchPattern C# (CSharp) Method

        private QilNode MatchPattern(QilNode pattern, QilIterator testNode)
        {
            QilList list;
            if (pattern.NodeType == QilNodeType.Error)
            {
                // Invalid pattern
                return pattern;
            }
            else if (pattern.NodeType == QilNodeType.Sequence)
            {
                list = (QilList)pattern;
                Debug.Assert(0 < list.Count, "Pattern should have at least one filter");
            }
            else
            {
                list = _f.BaseFactory.Sequence();
                list.Add(pattern);
            }

            QilNode result = _f.False();
            for (int i = list.Count - 1; 0 <= i; i--)
            {
                QilLoop filter = (QilLoop)list[i];
                _ptrnBuilder.AssertFilter(filter);
                result = _f.Or(
                    _refReplacer.Replace(filter.Body, filter.Variable, testNode),
                    result
                );
            }
            return result;
        }