/// <inheritdoc/>
protected override Provider VisitAggregate(AggregateProvider provider)
{
OnRecursionEntrance(provider);
var source = VisitCompilable(provider.Source);
var resultParameters = OnRecursionExit(provider);
if (source == provider.Source)
{
return(provider);
}
if (resultParameters == null)
{
var acd = new List <AggregateColumnDescriptor>(provider.AggregateColumns.Length);
acd.AddRange(provider.AggregateColumns.Select(ac => new AggregateColumnDescriptor(ac.Name, ac.SourceIndex, ac.AggregateType)));
return(new AggregateProvider(source, provider.GroupColumnIndexes, acd.ToArray()));
}
var result = (Pair <int[], AggregateColumnDescriptor[]>)resultParameters;
return(new AggregateProvider(source, result.First, result.Second));
}
/// <summary> /// Visits <see cref="AggregateProvider"/>. /// </summary> /// <param name="provider">Aggregate provider.</param> /// <returns></returns> protected abstract Provider VisitAggregate(AggregateProvider provider);
