(define (gensym:gensym)
(sym (string "gensym-" (inc gensym:counter))))
(define-macro (closure varval-pairs body)
(let (alist (map (fn(x) (list (x 0) (gensym) (eval (x 1))))
(explode varval-pairs 2)))
(bind (map (fn (x) (rest x)) alist))
(dolist (x alist)
(set-ref-all (x 0) body (x 1)))
body))
(set 'up-down
(closure (a 0 b 99)
(lambda () (list (++ a) (-- b)))))
> (up-down)
(1 98)
> (up-down)
(2 97)
> (up-down)
(3 96)
> (println up-down)
(lambda () (list (++ gensym:gensym-14) (-- gensym:gensym-15)))
Slightly improved, and with an example in which two lambdas share a variable.
(define-macro (closure varval-pairs)
(let (body (cons 'begin (args))
alist (map (fn(x) (list (x 0) (gensym) (eval (x 1))))
(explode varval-pairs 2)))
(bind (map (fn (x) (rest x)) alist))
(dolist (x alist)
(set-ref-all (x 0) body (x 1)))
(eval body)))
(closure (count 0)
(setq up (fn()(++ count))) (setq down (fn()(-- count))))
: (up)
1
: (up)
2
: (up)
3
: (down)
2
: (down)
1
Nice application of 'gensym'.
For a different way of doing it see here:
http://www.newlisp.org/index.cgi?def-static
The difference to WJ's solution is, that it puts each function in it's own namespace via a default functor.
Thanks. I think it would be nice if gensym were built into newLISP.
It seems that gensym isn't really needed anymore.
One can simply do (sym (uuid)).
Yes, that works well and those things