>Here's a quick and dirty function for determining leap years:
>
>Function LeapYear
>* dCheck_date is some date in the year you wish to check
>Parameters dCheck_date
>local nYear
>m.nYear = STR(YEAR(m.dCheck_date),4)
>return !empty(CTOD("02/29/"+m.nYear))

That's Set Date dependent (in my case it would return empty for all millenia, for no years have 29 months here). We'd either have to do some internal Set Date (saving, setting, restoring), or use the new strict date syntax, like

return !empty(Eval("{^"+ STR(YEAR(m.dCheck_date),4)+"/02/29}"))

Works in VFP5.0, tested.