ice-9/stack-catch.scm

   1 ;;; installed-scm-file
   2
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  44
  45 (define-module (ice-9 stack-catch)
  46   :export (stack-catch))
  47
  48 (define (stack-catch key thunk handler)
  49   "Like @code{catch}, invoke @var{thunk} in the dynamic context of
  50 @var{handler} for exceptions matching @var{key}, but also save the
  51 current stack state in the @var{the-last-stack} fluid, for the purpose
  52 of debugging or re-throwing of an error.  If thunk throws to the
  53 symbol @var{key}, then @var{handler} is invoked this way:\n
  54 @example
  55 (handler key args ...)
  56 @end example\n
  57 @var{key} is a symbol or #t.\n
  58 @var{thunk} takes no arguments.  If @var{thunk} returns normally, that
  59 is the return value of @code{catch}.\n
  60 Handler is invoked outside the scope of its own @code{catch}.  If
  61 @var{handler} again throws to the same key, a new handler from further
  62 up the call chain is invoked.\n
  63 If the key is @code{#t}, then a throw to @emph{any} symbol will match
  64 this call to @code{catch}."
  65   (catch key
  66          (lambda ()
  67            (lazy-catch key
  68                        thunk
  69                        lazy-handler-dispatch))
  70          handler))