System.Xml.Xsl.XsltOld.TemplateAction.AnalyzePriority C# (CSharp) Method

        private void AnalyzePriority(Compiler compiler) {
            NavigatorInput input = compiler.Input;

            if (!Double.IsNaN(this.priority) || this.matchKey == Compiler.InvalidQueryKey) {
                return;
            }
            // Split Unions:
            TheQuery theQuery = (TheQuery)compiler.QueryStore[this.MatchKey];
            CompiledXpathExpr expr = (CompiledXpathExpr)theQuery.CompiledQuery;
            Query query = expr.QueryTree;
            UnionExpr union;
            while ((union = query as UnionExpr) != null) {
                Debug.Assert(!(union.qy2 is UnionExpr), "only qy1 can be union");
                TemplateAction copy = this.CloneWithoutName();
                compiler.QueryStore.Add(new TheQuery(
                    new CompiledXpathExpr(union.qy2, expr.Expression, false),
                    theQuery._ScopeManager
                ));
                copy.matchKey = compiler.QueryStore.Count - 1;
                copy.priority = union.qy2.XsltDefaultPriority;
                compiler.AddTemplate(copy);

                query = union.qy1;
            }
            if (expr.QueryTree != query) {
                // query was splitted and we need create new TheQuery for this template
                compiler.QueryStore[this.MatchKey] = new TheQuery(
                    new CompiledXpathExpr(query, expr.Expression, false),
                    theQuery._ScopeManager
                );
            }
            this.priority = query.XsltDefaultPriority;
        }