ikarus/scheme/ikarus.exceptions.ss

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;;; Ikarus Scheme -- A compiler for R6RS Scheme.
;;; Copyright (C) 2006,2007 Abdulaziz Ghuloum
;;;
;;; This program is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License version 3 as
;;; published by the Free Software Foundation.
;;;
;;; This program is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program. If not, see <http://www.gnu.org/licenses/>.
(library (ikarus exceptions)
(export with-exception-handler raise raise-continuable error)
(import
(only (rnrs) condition make-non-continuable-violation
make-message-condition make-error make-who-condition
make-irritants-condition)
(except (ikarus)
with-exception-handler raise raise-continuable error))
(define handlers
(make-parameter
(list
(lambda (x)
(printf "unhandled exception:\n")
(print-condition x)
(exit -1)))))
(define (with-exception-handler handler proc2)
(unless (procedure? handler)
(error 'with-exception-handler
"handler is not a procedure" handler))
(unless (procedure? proc2)
(error 'with-exception-handler "not a procedure" proc2))
(parameterize ([handlers (cons handler (handlers))])
(proc2)))
(define (raise-continuable x)
(let ([h* (handlers)])
(let ([h (car h*)] [h* (cdr h*)])
(parameterize ([handlers h*])
(h x)))))
(define (raise x)
(let ([h* (handlers)])
(let ([h (car h*)] [h* (cdr h*)])
(parameterize ([handlers h*])
(h x)
(raise
(condition
(make-non-continuable-violation)
(make-message-condition "handler returned")))))))
(define (error who msg . irritants)
(unless (string? msg)
(error 'error "message is not a string" msg))
(raise
(condition
(make-error)
(if who (make-who-condition who) (condition))
(make-message-condition msg)
(if (null? irritants)
(condition)
(make-irritants-condition irritants)))))
)