Activate appointments found in `org-agenda-files'.
With a C-u prefix, refresh the list of
appointments.
If FILTER is t, interactively prompt the user for a regular
expression, and filter out entries that don't match it.
If FILTER is a string, use this string as a regular expression
for filtering entries out.
If FILTER is a function, filter out entries against which
calling the function returns nil. This function takes one
argument: an entry from `org-agenda-get-day-entries'.
FILTER can also be an alist with the car of each cell being
either 'headline or 'category. For example:
'((headline "IMPORTANT")
(category "Work"))
will only add headlines containing IMPORTANT or headlines
belonging to the "Work" category.
ARGS are symbols indicating what kind of entries to consider.
By default `org-agenda-to-appt' will use :deadline, :scheduled
and :timestamp entries. See the docstring of `org-diary' for
details and examples.
If an entry has a APPT_WARNTIME property, its value will be used
to override `appt-message-warning-time'.
(fn &optional REFRESH FILTER &rest ARGS)