The -exit- Command
Suppose you are seven levels deep in -do-s. That is, you have encountered seven nested -do- statements on the way to the present unit. The statement “exit 2” will take you out two levels. The next statement to be executed is the statement which follows the sixth -do-. A blank -exit-command (blank tag) takes you immediately to the statement following the first -do-. (Such operations are occasionally useful.) Notice that encountering a unit command at the end of a done subroutine will cause an automatic “exit 1”. It is superfluous to put “exit 1” at the end of a unit, since this effect is automatic.