- time-period-preceding TIME-PERIOD-1 TIME-PERIOD-2procedure
- time-period-preceding TIME-PERIOD-1 TIME-PERIOD-2procedure
Return the portion of TIME-PERIOD-1 before TIME-PERIOD-2 or #f when it doesn't precede.
Return the portion of TIME-PERIOD-1 before TIME-PERIOD-2 or #f when it doesn't precede.