2.16 Guarded Evaluation: when and unless
Effects If...: when and unless in Guide: Racket introduces when and unless.
(when test-expr body ...+) |
Evaluates test-expr. If the result is #f, then
the result of the when expression is
#<void>. Otherwise, the bodys are evaluated, and the
last body is in tail position with respect to the
when form.
Examples: | ||||||||
|
(unless test-expr body ...+) |
Examples: | ||||||||
|