org-read-date-get-relative

org-read-date-get-relative is a compiled Lisp function in `org.el'.

(org-read-date-get-relative S TODAY DEFAULT)

Check string S for special relative date string.
TODAY and DEFAULT are internal times, for today and for a default.
Return shift list (N what def-flag)
WHAT is "d", "w", "m", or "y" for day, week, month, year.
N is the number of WHATs to shift.
DEF-FLAG is t when a double ++ or -- indicates shift relative to
the DEFAULT date rather than TODAY.