~ chicken-core (chicken-5) /tests/dwindtst.scm

 1;;;; "dwindtst.scm", routines for characterizing dynamic-wind.
 2;Copyright (C) 1992 Aubrey Jaffer
 3;
 4;Permission to copy this software, to modify it, to redistribute it,
 5;to distribute modified versions, and to use it for any purpose is
 6;granted, subject to the following restrictions and understandings.
 7;
 8;1.  Any copy made of this software must include this copyright notice
 9;in full.
10;
11;2.  I have made no warranty or representation that the operation of
12;this software will be error-free, and I am under no obligation to
13;provide any services, by way of maintenance, update, or otherwise.
14;
15;3.  In conjunction with products arising from the use of this
16;material, there shall be no use of my name in any advertising,
17;promotional, or sales literature without prior written consent in
18;each case.
19
20(define (dwtest n)
21  (define cont #f)
22  (display "testing escape from thunk") (display n) (newline)
23  (display "visiting:") (newline)
24  (call-with-current-continuation
25   (lambda (x) (set! cont x)))
26  (if n
27      (dynamic-wind
28       (lambda ()
29	 (display "thunk1") (newline)
30	 (if (eqv? n 1) (let ((ntmp n))
31			  (set! n #f)
32			  (cont ntmp))))
33       (lambda ()
34	 (display "thunk2") (newline)
35	 (if (eqv? n 2) (let ((ntmp n))
36			  (set! n #f)
37			  (cont ntmp))))
38       (lambda ()
39	 (display "thunk3") (newline)
40	 (if (eqv? n 3) (let ((ntmp n))
41			  (set! n #f)
42			  (cont ntmp)))))))
43(define (dwctest n)
44  (define cont #f)
45  (define ccont #f)
46  (display "creating continuation thunk") (newline)
47  (display "visiting:") (newline)
48  (call-with-current-continuation
49   (lambda (x) (set! cont x)))
50  (if n (set! n (- n)))
51  (if n
52      (dynamic-wind
53       (lambda ()
54	 (display "thunk1") (newline)
55	 (if (eqv? n 1) (let ((ntmp n))
56			  (set! n #f)
57			  (cont ntmp))))
58       (lambda ()
59	 (call-with-current-continuation
60	  (lambda (x) (set! ccont x)))
61	 (display "thunk2") (newline)
62	 (if (eqv? n 2) (let ((ntmp n))
63			  (set! n #f)
64			  (cont ntmp))))
65       (lambda ()
66	 (display "thunk3") (newline)
67	 (if (eqv? n 3) (let ((ntmp n))
68			  (set! n #f)
69			  (cont ntmp))))))
70  (cond
71   (n
72    (set! n (- n))
73    (display "testing escape from continuation thunk") (display n) (newline)
74    (display "visiting:") (newline)
75    (ccont #f))))
76
77(dwtest 1) (dwtest 2) (dwtest 3)
78(dwctest 1) (dwctest 2) (dwctest 3)