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

        private void CompileDataTypeAttribute(string attValue, bool fwdCompat, ref QilNode select, out QilNode select2)
        {
            const string DtText = "text";
            const string DtNumber = "number";
            QilNode result = CompileStringAvt(attValue);
            if (result != null)
            {
                if (result.NodeType == QilNodeType.LiteralString)
                {
                    string dataType = (string)(QilLiteral)result;
                    if (dataType == DtNumber)
                    {
                        select = _f.ConvertToNumber(select);
                        select2 = null;
                        return;
                    }
                    else if (dataType == DtText)
                    {
                        // fall through to default case
                    }
                    else
                    {
                        if (!fwdCompat)
                        {
                            // check for qname-but-not-ncname
                            string prefix, local, nsUri;
                            bool isValid = _compiler.ParseQName(dataType, out prefix, out local, (IErrorHelper)this);
                            nsUri = isValid ? ResolvePrefix(/*ignoreDefaultNs:*/true, prefix) : _compiler.CreatePhantomNamespace();

                            if (nsUri.Length == 0)
                            {
                                // this is a ncname; we might report SR.Xslt_InvalidAttrValue,
                                // but the following error message is more user friendly
                            }
                            ReportError(/*[XT_034]*/SR.Xslt_BistateAttribute, "data-type", DtText, DtNumber);
                        }
                        // fall through to default case
                    }
                }
                else
                {
                    // Precalculate its value outside of for-each loop
                    QilIterator dt, qname;

                    result = _f.Loop(dt = _f.Let(result),
                        _f.Conditional(_f.Eq(dt, _f.String(DtNumber)), _f.False(),
                        _f.Conditional(_f.Eq(dt, _f.String(DtText)), _f.True(),
                        fwdCompat ? _f.True() :
                        _f.Loop(qname = _f.Let(ResolveQNameDynamic(/*ignoreDefaultNs:*/true, dt)),
                            _f.Error(_lastScope.SourceLine,
                                SR.Xslt_BistateAttribute, "data-type", DtText, DtNumber
                            )
                        )
                    )));

                    QilIterator text = _f.Let(result);
                    _varHelper.AddVariable(text);

                    // Make two sort keys since heterogenous sort keys are not allowed
                    select2 = select.DeepClone(_f.BaseFactory);
                    select = _f.Conditional(text, _f.ConvertToString(select), _f.String(string.Empty));
                    select2 = _f.Conditional(text, _f.Double(0), _f.ConvertToNumber(select2));
                    return;
                }
            }

            // Default case
            select = _f.ConvertToString(select);
            select2 = null;
        }