;
IF -- Evaluates a given expression, and executes an action-list conditionally.
(The IF command serves the same purpose as an if/then or if/then/else
construct in most high-level languages.)
> IF x > 0 [EXAMINE x]
> IF x > 0 [EXAMINE x] -ELSE [EXAMINE y]
> IF ((x < y) AND (y < z)) [DELETE -B -ALL; BREAKPOINT f1\; GO]
> IF flag [PRINT 'flag is on'] -ELSE [PRINT 'flag is off']
> BREAKPOINT 24 -DO [IF ((x << n) < 16) [PRINT x] ]