Returns a list with weekday, day, month, year and total days of the month of local-time object

get-timestamp-data.lisp

(defun get-timestamp-data (timestamp)
  "Returns a list with weekday, day, month, year and  total days of the month.
   *ISO compatible weekday number (monday=1, sunday=7)
   *day of month
   *numeric month
   *year
   *numeric  total-days-of-month"
  (let ((day-of-week nil)
	(day nil)
	(month nil)
	(year nil)
	(total-days-of-month nil)
	(date-data nil))
    ;; Create a list of subsequences in seq delimited by #\Space
    (setf date-data (split-sequence:split-sequence #\Space
						   (format-timestring nil
								      timestamp
								      :format
								      '((:iso-week-day)
									" "
									(:day)
									" "
									(:month)
									" "
									(:year)))))
    ;; string to integer
    (setf day-of-week (read-from-string (first date-data))
	  day (read-from-string (second date-data))
	  month (read-from-string (third date-data))
	  year (read-from-string (fourth date-data)))
    ;; get the total day of month
    (setf total-days-of-month (days-in-month month year))
    ;; finally return the information.
    (list day-of-week day month year total-days-of-month)))