🚀 go-pugleaf

As Pete Holzmann says, matherr() only catches math errors in library
functions.  You must use the SIG_FPE/setjmp/longjmp facilities to
handle "lower-level" math errors.

I found that it was really hard to recover from a general math error ---
what do you want to do on divide-by-zero, for example?  Generate a
largest-possible-value? print a message? ... The simplest thing to do
is to simply clear everything out and longjmp back to some point in
your code that precedes the failed operation (and your error-handler
doesn't necessarily know where that is).

Plug:  I am told that my rpn calculator is queued for c.b.i.p.  It includes
source code, and I use both the matherr() and the SIG_FPE code to handle
math errors.  I don't claim it's the best example of such stuff, but it
*is* a working example...