The feature to be considered is to assign a recurring task to a specific day, not based on the numerical date, but on a specific name'd date.

An algorithm for this is the primary concern as it has been determined that there are many use cases and many ways to solve them all individually. What has to be done is to find a solution to solve as many of these use cases as possible with one algorithm.

Example use cases

I have a meetup that I like to go to and would like to schedule the event as a recurring task. The meetup happens on the third wednesday of the month.

Stolen from stack overflow: This will give the day of the week as 0 = Sunday, 6 = Saturday. This result can easily be adjusted by adding a constant before or after the modulo 7.

Code Block:

dayOfWeek = (year*365 + trunc((year-1) / 4) - trunc((year-1) / 100) + trunc((year-1) / 400)) % 7