CasperSecurity
;;; installed-scm-file
;;;; Copyright (C) 2001, 2006, 2010 Free Software Foundation, Inc.
;;;;
;;;; This library is free software; you can redistribute it and/or
;;;; modify it under the terms of the GNU Lesser General Public
;;;; License as published by the Free Software Foundation; either
;;;; version 3 of the License, or (at your option) any later version.
;;;;
;;;; This library 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
;;;; Lesser General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU Lesser General Public
;;;; License along with this library; if not, write to the Free Software
;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;;;;
(define-module (ice-9 stack-catch)
#:use-module (ice-9 save-stack)
#:export (stack-catch))
(define (stack-catch key thunk handler)
"Like @code{catch}, invoke @var{thunk} in the dynamic context of
@var{handler} for exceptions matching @var{key}, but also save the
current stack state in the @var{the-last-stack} fluid, for the purpose
of debugging or re-throwing of an error. If thunk throws to the
symbol @var{key}, then @var{handler} is invoked this way:\n
@example
(handler key args ...)
@end example\n
@var{key} is a symbol or #t.\n
@var{thunk} takes no arguments. If @var{thunk} returns normally, that
is the return value of @code{catch}.\n
Handler is invoked outside the scope of its own @code{catch}. If
@var{handler} again throws to the same key, a new handler from further
up the call chain is invoked.\n
If the key is @code{#t}, then a throw to @emph{any} symbol will match
this call to @code{catch}."
(catch key
thunk
handler
(lambda (key . args)
;; Narrow by two more frames: this one, and the throw handler.
(save-stack 2)
(apply throw key args))))