Conditional structures: Difference between revisions

===[http://docs.racket-lang.org/reference/if.html#%28form._%28%28quote._~23~25kernel%29._if%29%29 if]===

If-expressions in Racket must have both branches

(if (< x 10)

"small"

===[http://docs.racket-lang.org/reference/when_unless.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._when%29%29 when/unless]===

One-sided conditional expressions use "when" and "unless". These are more convenient for side-effects since they have an implicit "begin" around their body, and you can also include new definitions

(when (< x 10)

(define y (* x 10))

===[http://docs.racket-lang.org/reference/if.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._cond%29%29 cond]===

Used for multiple conditions:

(printf "x is ~a\n"

(cond [(< x 1) "tiny"]

===[http://docs.racket-lang.org/reference/case.html#%28form._%28%28lib._racket%2Fprivate%2Fmore-scheme..rkt%29._case%29%29 case]===

Similar to a "switch" statement in other languages

(case x

[(1) "one"]