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