my @tmp=split/$separator/;  # e.g. , or | is the separator
my $last=pop @tmp; # get the last element
$last=$s/\s+//g;  #clean it up
#normally $last would be a number. If it is not a number but a unicode
# string, I want to throw an exception. The problem
# is that I get a  fatal malformed Utf-8 character error when I try either
if($last !~/\d/){...}
or if($last=~/[^/x00-\x7f]){...}