Add support for BYWEEKDAY

[jonocodes]

dateutils.rrule supports the byweekday parameter already:
http://dateutil.readthedocs.io/en/stable/rrule.html

Could this be added to icalendar?

[niccokunzmann]

@natashamm Thanks for working on this issue! I wonder: Do you think that this issue can be closed now? Is there anything else to do?

[natashamm]

The other issue I was thinking of is: what if someone generates an RRULE with BYDAY and BYWEEKDAY, do we want to throw an error or automatically replace one with the other? From what I understand about icalendar, I would say no.

If that is OK then I would say we can close the issue!

[niccokunzmann]

Since it is an assumption of the algorithm, I would say an assertion would do it.

[niccokunzmann]

@natashamm @jonocodes #511 was merged and released in v5.0.5. Can you check if this can be closed?

[natashamm]

Since it is an assumption of the algorithm, I would say an assertion would do it.

My bad - do you mean an assumption in https://dateutil.readthedocs.io/en/stable/rrule.html?

[niccokunzmann]

No. If we have these two arguments that mean the same and the value differs, what do we do? Which one is used? rrule can only take one of them, I assume. What are your thoughts?

[niccokunzmann]

Ok, thanks! I had a look. It seems that dateutil will handle the parsing of an rrule string and as such the question of how to convert this parameter is not necessary to answer in icalendar. Thanks for the work!
If there is any doubt whether this should be closed, please comment/re-open!