Data commit

Task/Generic-swap/EchoLisp/generic-swap.l

@@ -0,0 +1,20 @@
+;; 1)
+;; a macro will do it, as shown in Racket (same syntax)
+(define-syntax-rule (swap a b)
+    (let ([tmp a])
+    (set! a b)
+    (set! b tmp)))
+
+(define A 666)
+(define B "simon")
+(swap A B)
+A → "simon"
+B → 666
+
+;; 2)
+;; The list-swap! function allows to swap two items inside a list, regardless of their types
+;; This physically alters the list
+
+(define L ' ( 1 2 3 4 🎩 ))
+(list-swap! L 1 ' 🎩 )
+    → (🎩 2 3 4 1)