package TestPkg;
use Dispatch;

sub sub_a {
    # ...
}

sub sub_b {
    # ...
}

sub _sub_b_helper { # not part of the table!
    # ...
}

sub sub_c {
    print $_[0];
}

package main;
my $table = create_dptable TestPkg; # or TestPkg::create_dptable();
$table->{sub_c}->("Hello!");

##</code><code>##

package Dispatch;

sub import {
   my $pkg = (caller)[0];
   *{"${pkg}::create_dptable"} = sub {
        my %dispatch;
        my @oksymbols = grep {    !/^_/
                             && !/^create_dptable$/
                             && defined *{"${pkg}::$_"}{CODE} }
                        keys %{*{"${pkg}::"}};
        $dispatch{$_} = *{"${pkg}::$_"}{CODE}
            foreach ( @oksymbols );
        return \%dispatch
    };
}

1;