0. #lang racket/base
1. (let ([tag (make-continuation-prompt-tag)])
2.         (println "111")
3.         (println (string-append "222"
4.                 (call-with-continuation-prompt
5.                         (lambda ()
6.                                 (let ([data 0])
7.                                         (println (string-append "333"
8.                                                 (call-with-composable-continuation
9.                                                         (lambda (k)
10.                                                                 (println "---")
11.                                                                 (println (string-append "pop& " (k " push&")))
12.                                                                 ;; (abort-current-continuation tag "bbb")
13.                                                                 "666")
14.                                                         tag)))
15.                                         (println (string-append "zzz"
16.                                                 (call-with-composable-continuation
17.                                                         (lambda (k)
18.                                                                 (println "+++")
19.                                                                 (println (string-append "pop| " (k " push|")))
20.                                                                 ;; (abort-current-continuation tag "bbb")
21.                                                                 "ddd")
22.                                                         tag)))
23.                                         (println data)
24.                                         (set! data (+ data 1))
25.                                         (if (= data 56)
26.                                                 (abort-current-continuation tag "bbb")
27.                                                 "777")))
28.                         tag
29.                         (lambda (k)
30.                                 (println (string-append "888" k))
31.                                 "aaa"
32.                                 )))))
33.         (println "999")

=>

"111" "---" "333 push&" "+++" "zzz push|" 0 "pop& 777" "333666" "+++" "zzz push|" 1 "pop| 777" "zzzddd" 2 "pop& 777" "333666" "+++" "zzz push|" 3 "pop| 777" "zzzddd" 4 "pop| 777" "zzzddd" 5 "pop& 777" "333666" "+++" "zzz push|" 6 "pop| 777" "zzzddd" 7 "pop| 777" "zzzddd" 8 "pop| 777" "zzzddd" 9 "pop& 777" "333666" "+++" "zzz push|" 10 "pop| 777" "zzzddd" 11 "pop| 777" "zzzddd" 12 "pop| 777" "zzzddd" 13 "pop| 777" "zzzddd" 14 "pop& 777" "333666" "+++" "zzz push|" 15 "pop| 777" "zzzddd" 16 "pop| 777" "zzzddd" 17 "pop| 777" "zzzddd" 18 "pop| 777" "zzzddd" 19 "pop| 777" "zzzddd" 20 "pop& 777" "333666" "+++" "zzz push|" 21 "pop| 777" "zzzddd" 22 "pop| 777" "zzzddd" 23 "pop| 777" "zzzddd" 24 "pop| 777" "zzzddd" 25 "pop| 777" "zzzddd" 26 "pop| 777" "zzzddd" 27 "pop& 777" "333666" "+++" "zzz push|" 28 "pop| 777" "zzzddd" 29 "pop| 777" "zzzddd" 30 "pop| 777" "zzzddd" 31 "pop| 777" "zzzddd" 32 "pop| 777" "zzzddd" 33 "pop| 777" "zzzddd" 34 "pop| 777" "zzzddd" 35 "pop& 777" "333666" "+++" "zzz push|" 36 "pop| 777" "zzzddd" 37 "pop| 777" "zzzddd" 38 "pop| 777" "zzzddd" 39 "pop| 777" "zzzddd" 40 "pop| 777" "zzzddd" 41 "pop| 777" "zzzddd" 42 "pop| 777" "zzzddd" 43 "pop| 777" "zzzddd" 44 "pop& 777" "333666" "+++" "zzz push|" 45 "pop| 777" "zzzddd" 46 "pop| 777" "zzzddd" 47 "pop| 777" "zzzddd" 48 "pop| 777" "zzzddd" 49 "pop| 777" "zzzddd" 50 "pop| 777" "zzzddd" 51 "pop| 777" "zzzddd" 52 "pop| 777" "zzzddd" 53 "pop| 777" "zzzddd" 54 "pop& 777" "333666" "+++" "zzz push|" 55 "888bbb" "222aaa"

"999"