Re: Add seq-shuffle

[Adam Porter <adam@alphapapa.net>]

Hi Hugo,

Thanks, this is a gap in functionality that should be filled.

FWIW, in my listen.el package on ELPA, I have this function, the 
algorithm of which I copied from Chris Wellons's elfeed-shuffle function 
in his Elfeed package (which he placed into the Public Domain).

(defun listen-queue-shuffle (queue)
   "Shuffle QUEUE."
   (interactive (list (listen-queue-complete)))
   ;; Copied from `elfeed-shuffle'.
   (let* ((tracks (listen-queue-tracks queue))
          (current-track (listen-queue-current queue))
          n)
     (when current-track
       (cl-callf2 delete current-track tracks))
     (setf n (length tracks))
     ;; Don't use dotimes result (bug#16206)
     (dotimes (i n)
       (cl-rotatef (elt tracks i) (elt tracks (+ i (cl-random (- n i))))))
     (when current-track
       (push current-track tracks))
     (setf (listen-queue-tracks queue) tracks))
   (listen-queue--update-buffer queue))

I haven't benchmarked it against the version you posted, but I know that 
Chris did write it specifically for the sake of performance, so it would 
probably be worth considering.

--Adam