You can use keyword parameters without values to let invokers specify a CLIST option. For example, to let an invoker tell a CLIST to print its results, you can code the following:

PROC 0 PRINT

Then, if the invoker passes the keyword parameter PRINT:

EX clistname 'PRINT'

the variable PRINT takes the value PRINT. If the invoker does not pass the parameter PRINT, the variable PRINT takes a null value. Your CLIST can test the value to see if the invoker wants the print option. You can code this test using an IF-THEN-ELSE sequence:

PROC 0 PRINT
IF &PRINT = PRINT THEN (print results) /* If the value of PRINT = print …*/
ELSE …

(For more information about the IF-THEN-ELSE sequence, see The IF-THEN-ELSE sequence.)