package Class::WhenNeeded;
use File::Find;

sub import {
    my ($class, $top_package, $no_top_level) = @_;
    my @dirs = map { find_top_level_dir($_, $top_package) } @INC;
    foreach my $dir (@dirs) {
        find({
            wanted     => \&create_package_sub($no_top_level),
            preprocess => \&perl_packages,
        }, $dir);
    }
}

sub create_package_sub {   
    my $strip_top_level = shift;
    my $module       = make_module_name($File::Find::name, $strip_top_level);
    my $call_pack    = (caller(1))[1];
    if (defined &{$module}) {
        require Carp;
        Carp::croak "Function $module already defined";
    }
    *{$module} = sub {
        undef *{$module};
        eval <<"        END_EVAL";
        package $call_pack;
        use $module; # export goes to calling package?
        END_EVAL

        if ($@) {
            require Carp;
            Carp::croak "Could not load module: $module";
        }
        return $module;
    }
}