System.Xml.Xsl.IlGen.XmlILConstructInfo.Read C# (CSharp) Method

        public static XmlILConstructInfo Read(QilNode nd) {
            XmlILAnnotation ann = nd.Annotation as XmlILAnnotation;
            XmlILConstructInfo constrInfo = (ann != null) ? ann.ConstructInfo : null;

            if (constrInfo == null) {
                if (Default == null) {
                    constrInfo = new XmlILConstructInfo(QilNodeType.Unknown);
                    constrInfo.isReadOnly = true;

                    Default = constrInfo;
                }
                else {
                    constrInfo = Default;
                }
            }

            return constrInfo;
        }

        /// <summary>
        /// Recursively analyze the definition of a function.
        /// </summary>
        private static void AnalyzeDefinition(QilNode nd)
        {
            Debug.Assert(XmlILConstructInfo.Read(nd).PushToWriterLast,
                         "Only need to analyze expressions which will be compiled in push mode.");

            switch (nd.NodeType)
            {
            case QilNodeType.Invoke:
                // Invoke node can either be compiled as IteratorThenWriter, or Writer.
                // Since IteratorThenWriter involves caching the results of the function call
                // and iterating over them, .tailcall cannot be used
                if (XmlILConstructInfo.Read(nd).ConstructMethod == XmlILConstructMethod.Writer)
                {
                    OptimizerPatterns.Write(nd).AddPattern(OptimizerPatternName.TailCall);
                }
                break;

            case QilNodeType.Loop: {
                // Recursively analyze Loop return value
                QilLoop ndLoop = (QilLoop)nd;
                if (ndLoop.Variable.NodeType == QilNodeType.Let || !ndLoop.Variable.Binding.XmlType.MaybeMany)
                {
                    AnalyzeDefinition(ndLoop.Body);
                }
                break;
            }

            case QilNodeType.Sequence: {
                // Recursively analyze last expression in Sequence
                QilList ndSeq = (QilList)nd;
                if (ndSeq.Count > 0)
                {
                    AnalyzeDefinition(ndSeq[ndSeq.Count - 1]);
                }
                break;
            }

            case QilNodeType.Choice: {
                // Recursively analyze Choice branches
                QilChoice ndChoice = (QilChoice)nd;
                for (int i = 0; i < ndChoice.Branches.Count; i++)
                {
                    AnalyzeDefinition(ndChoice.Branches[i]);
                }
                break;
            }

            case QilNodeType.Conditional: {
                // Recursively analyze Conditional branches
                QilTernary ndCond = (QilTernary)nd;
                AnalyzeDefinition(ndCond.Center);
                AnalyzeDefinition(ndCond.Right);
                break;
            }

            case QilNodeType.Nop:
                AnalyzeDefinition(((QilUnary)nd).Child);
                break;
            }
        }