sub is_hex {
	my $self = shift if ref($_[0]); 
	my $value = shift;
	
	return unless defined $value;
	
	return if $value =~ /[^0-9a-f]/i;
	$value = lc($value);
	
	my $int = hex($value);
	return unless (defined $int);
	my $hex = sprintf "%x", $int;
	return $hex if ($hex eq $value);
	
	# handle zero stripping
	if (my ($z) = $value =~ /^(0+)/) {
		return "$z$hex" if ("$z$hex" eq $value);
	}
	
	return;
}

##</code><code>##

use warnings;
use strict;
use Data::Validate qw(:math);

my @data = qw(1234 ABCD 0x1234 foo 0xABCD bar);

foreach my $val (@data) {
  if (defined(is_hex($val))) {
		print "$val\tis hex";
	} else {
		print "$val\tis not hex";
	}
}
__END__

##</code><code>##

$ perl -l 629540.pl
1234    is hex
ABCD    is hex
0x1234  is not hex
foo     is not hex
0xABCD  is not hex
bar     is not hex