Conditions

if_ok command
if_not_ok command
if_eof command
if_not_eof command

The first two of these are tests of the return code from the last processor call, and are used primarily for controlling flow after calling a filter. Values of the return code $\leq0$ are considered `ok' (or event passes a filter) while values $>0$ are `not ok' (or event fails a filter). If the condition is met, then command is executed otherwise control passes to the next step in the program.

The last two test for ``internal EOFs'' returned the input processor INP and normally only used in conjunction with the Random Access Analyser RAA, see section 8.1.