TodayIF Returns Current Date being calculated when condition is True, else the NoDate date literal when false. Short form for the expression IF(condition, D, Nodate).  Usually used with an advanced math toolbox function. 

SYNTAX:

TodayIF(Condition)

EXAMPLES:

Example 1: Sum a fiscal year worth of values, starting on July 1st and ending on June 30th.

GETSUM(C5, #7/1/-1 TO TODAYIF(D=#6/30))

C5 : Get the average over time of variable 5
#7/1/-1 : From July 1st of last year
TODAYIF(D=#6/30) : To today, if today is June 30th

Example 2: Return the Date Number (Number of the days since Dec 31, 1899) if the current date is Aug 6th

TODAYIF(D=#8/6)