If you're using the constant package then you could just look at the %constant::declared hash e.g

require Your::Module;

my $pkg = 'Your::Module';

for(grep /^$pkg\::/, keys %constant::declared) {
  my($name) = /::(\w+)$/;
  my $val   = $pkg->can($name)->();

  print "$name: $val\n";
}
[download]

So there we just look for the constants that have been declared in Your::Module, grab the constant name, execute the constant sub of that name for the value, and then print them both out.