CGI::Untaint::printable - validate as a printable value
my $name = $handler->extract(-as_printable => 'name');
This Input Handler verifies that it is dealing with an 'printable' string i.e.
characters in the range \040-\377 (plus \r and \n).
The empty string is taken to be printable.
This is occasionally a useful 'fallback' pattern, but in general you will want
to write your own patterns to be stricter.