;; Packet Forth's spartan interface contains:

;; (pf-push item)   pushes an item on the data stack.
;; (pf-pop)         pops an item from the data stack.
;; (pf-exec code)   executes code. 
;;                  symbol: lookup + execute xt
;;                  list/string: interpret
;; (pf-eval)        evaluates expression on tos

;; The stuff below defines some scheme specific glue
;; to map pf operations to scheme functions.

;; shortcuts
(define exec pf-exec)
(define pop pf-pop)
(define push pf-push)
(defmacro pf (code) 
  `(begin (exec ,code) (pop)))

;; basic io
(define (grab) (pf 'grab))
(define (blit frame) (pf `(,frame blit undef)))

;; our killer app
(define (hot-demo) (blit (grab)) (hot-demo))