Code Help for Trading Day

[Greg Hunt <greghunt@xxxxxxxxxxxx>]

Can someone please correct this function for me?
In my EL library; not sure where it came from or why it doesn't work.
TIA.
Dr. Greg Hunt

{TRADING DAY OF THE MONTH
}
Vars: Mo(0), TradeDay(0);

Mo = Month(Date);
TradeDay = iff(Mo <> Mo[1], 1, TradeDay + 1);