                          '()))

(define-condition-type &amp;message &amp;condition
  message-condition?
  (message condition-message))

(define-condition-type &amp;serious &amp;condition
  serious-condition?)

(define-condition-type &amp;error &amp;serious
  error?)
</pre><h1>References</h1>
<ul><li><a href="http://srfi.schemers.org/srfi-12/">SRFI 12: Exception Handling</a>
by William Clinger, R. Kent Dybvig, Matthew Flatt, and Marc Feeley</li>
<li><a href="http://www.swiss.ai.mit.edu/ftpdir/scheme-mail/HT