System.Xml.Xsl.XsltOld.ContainerAction.CompileKey C# (CSharp) Method

        internal void CompileKey(Compiler compiler){
            NavigatorInput input    = compiler.Input;
            string         element  = input.LocalName;
            int            MatchKey = Compiler.InvalidQueryKey;
            int            UseKey   = Compiler.InvalidQueryKey;

            XmlQualifiedName Name = null;
            if (input.MoveToFirstAttribute()) {
                do {
                    string nspace = input.NamespaceURI;
                    string name   = input.LocalName;
                    string value  = input.Value;

                    if (! Keywords.Equals(nspace, input.Atoms.Empty)) continue;

					if (Keywords.Equals(name, input.Atoms.Name)) {
                        Name = compiler.CreateXPathQName(value);
                    }
                    else if (Keywords.Equals(name, input.Atoms.Match)) {
                        MatchKey = compiler.AddQuery(value, /*allowVars:*/false, /*allowKey*/false, /*pattern*/true);
                    }
                    else if (Keywords.Equals(name, input.Atoms.Use)) {
                        UseKey = compiler.AddQuery(value, /*allowVars:*/false, /*allowKey*/false, /*pattern*/false);
                    }
                    else {
                        if (! compiler.ForwardCompatibility) {
                            throw XsltException.Create(Res.Xslt_InvalidAttribute, name, element);
                        }
                    }
                }
                while(input.MoveToNextAttribute());
                input.ToParent();
            }

            CheckRequiredAttribute(compiler, MatchKey != Compiler.InvalidQueryKey, Keywords.s_Match);
            CheckRequiredAttribute(compiler, UseKey   != Compiler.InvalidQueryKey, Keywords.s_Use  );
            CheckRequiredAttribute(compiler, Name     != null                    , Keywords.s_Name );

            compiler.InsertKey(Name, MatchKey, UseKey);
        }