In role Dateish§
See primary documentation in context for method weekday-of-month
method weekday-of-month(Date: --> Int)
Returns a number (1..5) indicating the number of times a particular day-of-week has occurred so far during that month, the day itself included.
say Date.new("2003-06-09").weekday-of-month; # OUTPUT: «2» (second Monday of the month)