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; Copyright (c) 1993-1999 by Richard Kelsey and Jonathan Rees. See file COPYING.
; --------------------
; Fake interrupt and exception system.
; This needs to be reconciled with alt/primitives.scm.
(define (with-exceptions thunk)
(with-handler
(lambda (c punt)
(cond ((and (exception? c)
(procedure? (get-exception-handler)))
(handle-exception-carefully c))
((interrupt? c)
(if (not (deal-with-interrupt c))
(punt)))
;; ((vm-return? c)
;; (vm-return (cadr c)))
(else
(punt))))
thunk))
(define (handle-exception-carefully c)
(display "(Exception: ") (write c) (display ")") (newline)
(noting-exceptional-context c
(lambda ()
(raise-exception (exception-opcode c)
(exception-arguments c)))))
(define (noting-exceptional-context c thunk)
(call-with-current-continuation
(lambda (k)
;; Save for future inspection, just in case.
(set! *exceptional-context* (cons c k))
(thunk))))
(define *exceptional-context* #f)
(define (deal-with-interrupt c)
(noting-exceptional-context c
(lambda ()
(maybe-handle-interrupt
(if (and (pair? (cdr c)) (integer? (cadr c)))
(cadr c)
(enum interrupt keyboard))))))
; (define (poll-for-interrupts) ...)
; Get the whole thing started
(define (?start-with-exceptions entry-point arg)
(with-exceptions
(lambda ()
(?start entry-point arg))))
(define (in struct form)
(eval form (structure-package struct)))
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