The following functions do not exist within indexima. However, you achieve your goal by applying the following formulas.

Weekday

(8 + DATEDIFF(mydate,NEXT_DAY(CAST(mydate AS DATE),'SU')))
CODE

WeekNumber

FLOOR((14 + DATEDIFF( mydate, TRUNC(mydate,'YY') ) + DATEDIFF( TRUNC(mydate,'YY'), NEXT_DAY(TRUNC(mydate, 'YY'),'SU'))) /7)
CODE