use strict ;
  use warnings ;

  use Encode qw(_utf8_on) ;

  for my $r ("\xC2\xAB \x61\x68\x61 \xC2\xBB", "\xC2\x7E \x61\x68\x61 \x80\xC0") {
    for my $utf (0..1) {
      _utf8_on($r) if $utf ;
      printf "'%s', %d/%d %s\n", raw(unpack('a*', $r)) ;
    } ;
  } ;

  sub raw {
    my ($s) = @_ ;

    my ($b, $q) ;
    { use bytes ;
      $b = length($s) ;
      $q = join '', map { ($_ >= 0x20) && ($_ <= 0x7E) ? chr($_) : sprintf('\\x%02X', $_)
                        } unpack('C*', $s) ;
    } ;

    return ($q, length($s), $b, utf8::is_utf8($s) ? 'utf8' : 'not utf8') ;
  } ;

##</code><code>##

  my $s = "C2AB2061686120C2BB" ; _utf8_on($s) ;

  for my $unp ('a*', 'U0a*', 'C0a*') {
    my ($q, $b, $l, $u) = raw(unpack($unp, pack('H*', $s))) ;
  print "unpack('$unp', pack('H*', \$s)) -> '$q', $l/$b $u\n" ;
} ;

##</code><code>##

  my $s = "C2AB2061686120C2BB" ;

  for my $unp ('a*', 'U0a*', 'C0a*') {
    printf "unpack('$unp', pack('U0H*', $s)) -> '%s', %d/%d %s\n",
        raw(unpack( $unp,  pack('U0H*', $s))) ;
  } ;

##</code><code>##

  for my $s ("C2AB2041686120C2BB", "C27E204168612080C0") {
    printf "pack('U0H*', $s) -> '%s', %d/%d %s\n",
        raw(pack('U0H*', $s)) ;
    printf "unpack('a*', pack('U0H*', $s)) -> '%s', %d/%d %s\n",
        raw(unpack('a*', pack('U0H*', $s))) ;
  } ;

##</code><code>##

  sub dehex {
    my ($s) = @_ ;
    $s =~ s/0[xX]((?:[0-9A-Fa-f]{2})+)/pack('U0H*', $1)/eg ;
    return $s if utf8::valid($s) ;
    ... worry ...  return undef ??
  } ;