Use `,' to denote list

* undone/main.scm (add): When encountering a value that starts with
  `,', assume that it should be turned into a list.

undone/main.scm

@@ -127,9 +127,14 @@
                  (append
                   `((content . ,(read-delimited "")))
                   (map (lambda (arg)
-                         (let ((pair (string-split arg #\=)))
-                           (cons (string->symbol (car pair))
-                                 (cadr pair))))
+                         (let* ((pair (string-split arg #\=))
+                                (var (string->symbol (car pair)))
+                                (val (cadr pair)))
+                           (if (char=? (string-ref val 0) #\,)
+                               (set! val (string-split
+                                          (substring val 1) #\,)))
+
+                           (cons var val)))
                        args))))))
 
 (define-view default