"Real" Exceptions

Before Perl 5.005, $@ could only be a string
If you passed a ref to die(), it was stringified
Since 5.005, if you pass a ref, it is stored as is
So now we can do this:

eval { die { error => 'Bad SQL',
             sql => $sql,
             bound_vars => \@bound_vars } };
if ($@)
{
    warn "Error: $@->{error}\n";
    warn "SQL: $@->{sql}\n" if exists $@->{sql};
}