-

utils.rkt

@@ -0,0 +1,22 @@
+#lang racket/base
+
+(provide while)
+
+(define-syntax while
+  (syntax-rules ()
+    ((_ cond
+        body ...)
+     (letrec ((while (λ ()
+                       (if cond
+                           (begin
+                             (displayln "cond = true")
+                             (begin body ...)
+                             (while))
+                           (begin
+                             (displayln "cond = false")
+                             'done)))
+                     ))
+       (while)))
+    )
+  )
+