45 lines
1.5 KiB
Scheme
45 lines
1.5 KiB
Scheme
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; Copyright (c) 1993, 1994 Richard Kelsey and Jonathan Rees. See file COPYING.
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(define (compose-continuation proc cont)
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(primitive-cwcc
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(lambda (k)
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(with-continuation cont ;(if cont cont null-continuation)
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(lambda ()
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(proc (primitive-cwcc
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(lambda (k2) (with-continuation k (lambda () k2))))))))))
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; Old definition that relies on details of VM architecture:
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;(define null-continuation #f)
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;(define null-continuation (make-continuation 4 #f)) ;temp kludge
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;(continuation-set! null-continuation 1 0)
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;(continuation-set! null-continuation 2
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; ;; op/trap = 140
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; (segment-data->template (make-code-vector 1 140) #f '()))
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;(put 'primitive-cwcc 'scheme-indent-hook 0)
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;(put 'with-continuation 'scheme-indent-hook 1)
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;(define compose-continuation
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; (let ((tem
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; (let ((cv (make-code-vector 6 0)))
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; (code-vector-set! cv 0 op/push) ;push return value
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; (code-vector-set! cv 1 op/local) ;fetch procedure
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; (code-vector-set! cv 3 1) ;over = 1
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; (code-vector-set! cv 4 op/call)
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; (code-vector-set! cv 5 1) ;one argument
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; (segment-data->template cv 0 '()))))
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; (lambda (proc parent-cont)
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; (let ((cont (make-continuation 4 #f)))
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; (continuation-set! cont 0 parent-cont)
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; (continuation-set! cont 1 0) ;pc
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; (continuation-set! cont 2 tem) ;template
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; (continuation-set! cont 3 (vector #f proc)) ;environment
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; cont))))
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