From: cs731105
Subject: Having all underflows return 0?
Date: 
Message-ID: <1t0vrhINNi50@umbc8.umbc.edu>
I am a newcomer to the conditions system, so this may be obvious...

I am looking for a way to execute a body of code, but where any
floating point underflow errors just return 0 from their
*immediate* functions. Ie using handler-bind, I know how
to execute (expt 0.1 500) so that I get zero. And I can
arrange it so that 

(progn 
  (setq x (expt 0.1 500))
  (setq y 777))

returns 0. But I can't figure out how to arrange it so that x gets 0
but the assignment to y still gets executed. That is, in my real
problem I have an indeterminate number of forms, and want to execute all
of them, using 0 for underflows everywhere.

Can I do this? Or is my best option to define a Safe-Expt and Safe-Div,
etc, each of which returns 0 if there is an underflow?