A-M baby

Task/Generic-swap/Racket/generic-swap.rkt

@@ -0,0 +1,24 @@
+#lang racket/load
+
+(module swap racket
+  (provide swap)
+
+  ;; a simple macro to swap two variables
+  (define-syntax-rule (swap a b)
+    (let ([tmp a])
+      (set! a b)
+      (set! b tmp))))
+
+;; works fine in a statically typed setting
+(module typed typed/racket
+  (require 'swap)
+
+  (: x Integer)
+  (define x 3)
+
+  (: y Integer)
+  (define y 4)
+
+  (swap x y)
+  (printf "x is ~a~n" x)
+  (printf "y is ~a~n" y))