System.Xml.Xsl.IlGen.XmlILVisitor.CreateAggregator C# (CSharp) Method

        private QilNode CreateAggregator(QilUnary ndAgg, string aggName, XmlILStorageMethods methods, MethodInfo methAgg, MethodInfo methResult) {
            Label lblOnEnd = this.helper.DefineLabel();
            Type typAgg = methAgg.DeclaringType;
            LocalBuilder locAgg;

            // Aggregate agg;
            // agg.Create();
            locAgg = this.helper.DeclareLocal(aggName, typAgg);
            this.helper.Emit(OpCodes.Ldloca, locAgg);
            this.helper.Call(methods.AggCreate);

            // foreach (num in expr) {
            StartNestedIterator(ndAgg.Child, lblOnEnd);
            this.helper.Emit(OpCodes.Ldloca, locAgg);
            Visit(ndAgg.Child);

            //   agg.Aggregate(num);
            this.iterCurr.EnsureStackNoCache();
            this.iterCurr.EnsureItemStorageType(ndAgg.XmlType, GetItemStorageType(ndAgg));
            this.helper.Call(methAgg);
            this.helper.Emit(OpCodes.Ldloca, locAgg);

            // }
            this.iterCurr.LoopToEnd(lblOnEnd);

            // End nested iterator
            EndNestedIterator(ndAgg.Child);

            // If aggregate might be empty sequence, then generate code to handle this possibility
            if (ndAgg.XmlType.MaybeEmpty) {
                // if (agg.IsEmpty) goto LabelNextCtxt;
                this.helper.Call(methods.AggIsEmpty);
                this.helper.Emit(OpCodes.Brtrue, this.iterCurr.GetLabelNext());
                this.helper.Emit(OpCodes.Ldloca, locAgg);
            }

            // result = agg.Result;
            this.helper.Call(methResult);
            this.iterCurr.Storage = StorageDescriptor.Stack(GetItemStorageType(ndAgg), false);

            return ndAgg;
        }