The date operator #DAYOFWEEK indicates the day of week: 1 = Monday, 2= Tuesday, 3 = Wednesday, 4= Thursday, 5 = Friday, 6 = Saturday, and 7 = Sunday. This technique works because every date (in an expression) is the number of days since 1/1/1900.

; A_DT is a single date or an array of date(s) that you need to

; adjust (e.g., DOB field or #DATE in a transformation expression)


BegMth_DT:= -1 #MONTHROUND A_DT  & ; round to 1st of month

DaysToFri:= 5 - #DAYOFWEEK BegMth_DT & ; days from FRI

;    M T W T F  S  S   Day of week

;    1 2 3 4 5  6  7   #DAYOFWEEK

;    4 3 2 1 0 -1 -2   days to Friday


; if the first day of the month is Monday thru Friday, then

; BegMth + DaysToFri is a Friday, and it’s the first Firday

; of the current month. But if the first day of the month is
 all>

; Saturday or Sunday, then BegMth + DaysToFri is a Friday,

; but it’s the last Friday of the previous month! So, if the

; first day of the month is Saturday or Sunday, then 

; BegMth + DaysToFri + 7 is the first Friday of the current month


BegMth_DT + DaysToFri + (7 * (DaysToFri <0))