use Devel::Symdump;
my $obj = Devel::Symdump->rnew( $package_name ); 
my @methods = $obj->functions();
#  if you are sure private methods only start with underscore...
my @public_methods = grep {$_ !~ /^_/} @methods;

##</code><code>##

use Class::Inspector;
my $methods = Class::Inspector->methods( $package_name );
my $public_methods = Class::Inspector->methods( $package_name, 'public' );