IS_RECURRING_DATE

Checks whether a date falls on one of the dates of a recurring calendar appointment. The appointment is an object in the Context that belongs to the Appointments group (see Adding Appointment Objects) and owns the recurrence; its recurrence rule, exception dates and start time decide which dates match.

IS_RECURRING_DATE (date, object)

Cannot be used in the condition of a FIND action.

1. The date to check: an attribute of the Date type, a date constant or a calculation producing a date
2. The name of the object in the Context that owns the recurrence, written as a string constant (for example 'Task'); it must be a member of the Appointments group

Yes/No: Yes if the date is one of the dates of the recurrence (exception dates excluded), otherwise No. It is also No when there is no such object in the Context, or when the object has no recurrence or no start time.

IF IS_RECURRING_DATE (CURRENT_DATE, 'Task') = 'Yes' THEN SomeObject.SomeAttribute = 20 

CURRENT_DATE, DAY_OF_WEEK, NEXT_DAY_OF_WEEK, DATE_ADD