48 lines
1.3 KiB
Scheme
48 lines
1.3 KiB
Scheme
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(library (ikarus exceptions)
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(export with-exception-handler raise raise-continuable)
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(import
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(only (rnrs) condition make-non-continuable-violation
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make-message-condition)
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(except (ikarus)
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with-exception-handler raise raise-continuable))
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(define (print-condition x)
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(printf "CONDITION: ~s\n" x))
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(define handlers
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(make-parameter
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(list
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(lambda (x)
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(printf "unhandled exception:\n")
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(print-condition x)
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(exit -1)))))
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(define (with-exception-handler handler proc2)
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(unless (procedure? handler)
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(error 'with-exception-handler
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"handler ~s is not a procedure" handler))
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(unless (procedure? proc2)
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(error 'with-exception-handler
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"~s is not a procedure" proc2))
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(parameterize ([handlers (cons handler (handlers))])
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(proc2)))
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(define (raise-continuable x)
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(let ([h* (handlers)])
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(let ([h (car h*)] [h* (cdr h*)])
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(parameterize ([handlers h*])
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(h x)))))
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(define (raise x)
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(let ([h* (handlers)])
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(let ([h (car h*)] [h* (cdr h*)])
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(parameterize ([handlers h*])
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(h x)
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(raise
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(condition
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(make-non-continuable-violation)
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(make-message-condition "handler returned")))))))
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)
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