OPTION Y2PAST=1950
 SORT FIELDS=(21,6,Y2T,A,13,3,Y2X,D)

Y2PAST

Sets a century window of 1950–2049.

FIELDS

Sorts on a C'yymmdd' (or Z'yymmdd') date in positions 21-26 in ascending order, and on a P'dddyy' date in positions 13-15 in descending order. "Real" dates are sorted using the century window of 1950-2049. Special indicators are sorted correctly relative to the "real" dates.