#! /usr/bin/perl -w

use strict;
use warnings;
use feature qw(say);

my @hoge = (0, 1, 2, 3);

say join(
    ", ",
    listdouble(@hoge)
);

sub listdouble {
    my @list = @_;
    
    return map {
        $_ * 2
    } @_;
}