use 5.020;
use feature 'experimental::signatures';
no warnings 'experimental::signatures';

sub preload_module( $base_dir, $modulename ) {
    my $final_name = $modulename;
    $final_name =~ s!::!/!g;
    require "$base_dir/$final_name.pm";
}

BEGIN {
    preload_module('/some/perl5/dir', 'List::Util' );
    preload_module('/some/perl5/dir', 'Scalar::Util' );
    preload_module('/some/other/perl5/dir', 'Another::Module' );
}

use List::Util 'reduce';