This SRFI is strikingly similar to the system in SISC, but with one
deficiency.  In SISC, when an error is raised, a two argument handler
may intercept the error.  The first argument is an error message, which
is akin to the first argument in this SRFI's scheme.  The second is a
continuation captured at the location of the error, which among other
things allows the code to be restarted by applying the continuation with
a value that replaces the value that would have been returned by the
expression that raised the error.

This, combined with support for inspecting continuations, allows for
powerful debugging capabilities, and more flexibility in the
control of program flow when errors occur.

I refer you to
http://sisc.sourceforge.net/manual/html/ch03.html#ErrorHandling for a
more detailed description.

     Scott