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  1. #| stackoverflow.com/questions/34299077/
  2.        execute-following-call-cc-exp/34314930#34314930
  3.  
  4.     (let/cc done
  5.       ((let/cc esc
  6.          (done (+ 1 (let/cc k
  7.                       (esc k)))))
  8.        3)) ==>
  9. |#
  10. (print
  11.  (prog  (retval done arg1 func esc arg2 k arg3 arg4)
  12.     (setq done (lambda(x) (setq retval x) (go DONE)))
  13.      (setq arg1 3)
  14.       (setq esc  (lambda(x) (setq func x) (go ESC)))
  15.        (setq arg3 1)
  16.         (setq k  (lambda(x) (setq arg4 x) (go K)))
  17.         (setq arg4 (funcall esc k))
  18.         (/ 0 0)
  19.   K
  20.        (setq arg2 (+ arg3 arg4))
  21.       (setq func (funcall done arg2))
  22.       (/ 0 0)
  23.   ESC
  24.      (setq retval (funcall func arg1))
  25.   DONE
  26.     (print retval)  ; normally, (return retval) should be used
  27.   ))
  28.  
  29. #| stackoverflow.com/questions/16529475/
  30.        scheme-continuations-for-dummies/16531429#16531429
  31.  
  32. (prog (k retval)
  33.     (setq k (lambda (x)             ;; capture the current continuation:
  34.                     (setq retval x) ;;   set! the return value
  35.                     (go EXIT)))     ;;   and jump to exit point
  36.     (setq retval                    ;; get the value of the last expression,
  37.       (progn                        ;;   as usual, in the
  38.          ;;;;;;;;;;;;;;;;
  39.          (* 5 (funcall k 4))        ;; body of code
  40.          ;;;;;;;;;;;;;;;;
  41.          ))
  42.   EXIT                              ;; the goto label
  43.     (print retval))
  44. |#
Success #stdin #stdout 0s 10464KB
comments (?)
stdin 
Standard input is empty
stdout 
4 
NIL
https://ideone.com/HiVaJQ
https://stackoverflow.com/questions/16529475/scheme-continuations-for-dummies/16531429#16531429
language:
Common Lisp (clisp 2.49.92)
created:
8 years ago
visibility:
public

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