June 2018 Update

Task/Knuth-shuffle/PicoLisp/knuth-shuffle.l

@@ -1,7 +1,11 @@
-(de shuffle (Lst)
-   (make
-      (for (N (length Lst) (gt0 N))
-         (setq Lst
-            (conc
-               (cut (rand 0 (dec 'N)) 'Lst)
-               (prog (link (car Lst)) (cdr Lst)) ) ) ) ) )
+(seed (in "/dev/urandom" (rd 8)))
+
+(de knuth (Lst)
+   (for (N (length Lst) (>= N 2) (dec N))
+      (let I (rand 1 N)
+         (xchg (nth Lst N) (nth Lst I)) ) ) )
+
+(let L (range 1 15)
+   (println 'before L)
+   (knuth L)
+   (println 'after L) )