rewrite random-string in picolisp

...so I can use it in Termux.

random-string

-#!/usr/bin/env clisp
-; vim: filetype=lisp
-; random-string [length]
+#!/usr/bin/pil -argv dummy len
+# ^ bind first arg to `dummy`, second to `len`
+# if length is a file, it would be loaded
+# a bit of a hack around Picolisp's loading mechanism
+# random-string [length]
 
-(defvar *charset* "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
+# (time) is only down to seconds, can't just seed the PRNG on every call to select-random-item.
+(seed (+ (date) (time)))
+(setq *charset* (chop "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"))
 
-(defun select-random-item (seq)
-  (elt seq (random (length seq)
-                   ;; create a newly randomly seeded random state
-                   (make-random-state t))))
+(de select-random-item (seq)
+  (car (nth seq
+            (rand 1 (length seq)))))
 
-(defun random-string (&optional (len 16))
-  (map 'string
-       (lambda (x) (select-random-item *charset*))
-       (make-string len)))
+(de random-string (len)
+  (if (not len) (setq len 16))
+  (if (str? len) (setq len (format len)))
+  (mapcar '(() (select-random-item *charset*))
+          (range 1 len)))
 
-(format t (if *args*
-            (random-string (parse-integer (first *args*)))
-            (random-string)))
+(prinl (random-string len))
+(bye)
+# vim: filetype=picolisp