sub init {
    my $pkg = shift;
    my $proto = shift || $config->protocol();
    no strict 'refs'; 
    eval "require Bot::Protocol::$proto";
    if($@) {
        croak "Failed to load $proto.\n";
    }
}

##</code><code>##

# in the main
my $pkg = shift;
no strict 'refs';  
eval "require $pkg";
if($@) {
    croak "Failed to load $pkg: $@\n";
}
print foobar();
##</code><code>##

# in Foo.pm
package Foo;

use strict;
use Exporter;
use vars qw(@ISA @EXPORT);

@ISA = qw(Exporter);
@EXPORT = qw(foobar);

sub foobar {
    return "Foo!"; 
}
1;