private static SelectFromInfo GetOptionalSelectFrom(
CreateWindowDesc createWindowDesc,
StatementCompileTimeServices compileTimeServices)
{
if (createWindowDesc.AsEventTypeName == null) {
return null;
}
var eventType = StreamSpecCompiler.ResolveTypeName(
createWindowDesc.AsEventTypeName,
compileTimeServices.EventTypeCompileTimeResolver);
return new SelectFromInfo(eventType, createWindowDesc.AsEventTypeName);
}
