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;;test dynamic wind.
(define results '())
(define (collate obj)
(set! results (cons obj results)))
(define (display-results)
(for-each (lambda (x) (display x) (newline)) (reverse results)))
(define (f g h)
(dynamic-wind
(lambda () (collate 'b))
(lambda ()
(collate 'x)
(dynamic-wind
(lambda () (collate '-b))
(lambda ()
(let ((k #f))
(collate '-x)
(dynamic-wind
(lambda () (collate '--b1))
(lambda ()
(collate '--x1)
(g)
(collate '--y1))
(lambda () (collate '--a1)))
(dynamic-wind
(lambda () (collate '--b2))
(lambda ()
(collate '--x2)
(h)
(collate '--y2))
(lambda () (collate '--a2)))
(collate '-y)))
(lambda () (collate '-a)))
(collate 'y))
(lambda () (collate 'a))))
(define (t0)
(f (lambda () #f)
(lambda () #f)))
(define (t1)
(let ((k #f))
(f (lambda () (call/cc (lambda (kk) (set! k kk))))
(lambda () (if k (let ((kk k)) (set! k #f) (kk)))))))
(define (t2)
(with/fc (lambda (m e) #f)
(lambda () (f (lambda () (/ 1 0))
(lambda () #f)))))
;;the thing to watch out for is that b and a must always appear in
;;pairs and without interleaving unless the level (indicated by -)
;;deepens.
(set! results '())
(t0)
(display-results)
(set! results '())
(t1)
(display-results)
(set! results '())
(t2)
(display-results)
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