Editing While loop (section)

===Racket===
{{Further|Racket (programming language)|Scheme (programming language)}}
In Racket, as in other [[Scheme (programming language)|Scheme]] implementations, a ''named-let'' is a popular way to implement loops:
<syntaxhighlight lang="racket">
#lang racket
(define counter 5)
(define factorial 1)
(let loop ()
    (when (> counter 0)
        (set! factorial (* factorial counter))
        (set! counter (sub1 counter))
        (loop)))
(displayln factorial)
</syntaxhighlight>
Using a macro system, implementing a ''while'' loop is a trivial exercise (commonly used to introduce macros):
<syntaxhighlight lang="racket">
#lang racket
(define-syntax-rule (while test body ...) ; implements a while loop
    (let loop () (when test body ... (loop))))
(define counter 5)
(define factorial 1)
(while (> counter 0)
    (set! factorial (* factorial counter))
    (set! counter (sub1 counter)))
(displayln factorial)
</syntaxhighlight>
However, an imperative programming style is often discouraged in Scheme and Racket.