DATE2BASE:PROCEDURE
/* Convert given date to base - number of dates since 1/1/80 */
/* For this we need number of days in years before, plus */
/* date's number within a year */
/* Got func for number - JULIAN() */
ARG DA
PARSE VAR DA MM'/'DD'/'YY
VR=0
DO I=80 TO YY-1
   VR=VR+365
   IF LEAP(I) THEN VR=VR+1
END
VR=VR+JULIAN(DA)-1
RETURN VR

/***GET JULIAN */
JULIAN:PROCEDURE
/* Accepts date in US format as parm, return days' number in a year */
ARG DA
PARSE VAR DA MM'/'DD'/'YY
YY=Y2000(YY)

AD='31 28 31 30 31 30 31 31 30 31 30 31'
JULA=0
DO I=1 TO MM-1
   JULA=JULA+WORD(AD,I)
END
IF I>2 & LEAP(YY) THEN JULA=JULA+1
JULA=JULA+DD
RETURN JULA

/***GET Y2000 */
Y2000:PROCEDURE
/* Convert year in 4 digit format */
ARG YY
IF LENGTH(YY)=2 THEN DO
   IF YY>80 THEN YY='19'YY
   ELSE YY='20'YY
END
RETURN YY

/***GET LEAP */
LEAP:PROCEDURE
/* Return 1 if parm is leap year */
ARG YY
IF LENGTH(YY)=2 THEN DO
   IF YY>80 THEN YY='19'YY
   ELSE YY='20'YY
END
RETURN (YY%4*4=YY)