iCal allow defining a recurring event through the rrule. There may be many desired operations on rrule. Operations may include set operation (union, intersection..) & temporal operation(like before,after,in). For example, I may want to know whether an rrule entails another rrule. Is there any such library. I went through many libraries, I found that mostly they mostly generate the events. Is there any library which perform some reasoning and operations on rrule
The google-rfc-2445 project (Java) focuses on RRULEs and calculating their dates. While it hasn't been updated in a very long time, I use this library for one of my projects and it works very well.