Get installation order of interdependent module list

installation-order

#!/usr/bin/env perl
use strict;
use warnings;
use 5.010;
use Capture::Tiny qw(capture_stdout);
use List::MoreUtils qw(uniq);

sub prereqs;
my %modules;

for my $module (@ARGV) {
    my $deps = capture_stdout {
        system qw/cpanm -q --showdeps/, $module;
    };

    my %deps = map {;$_=>1} split /\n/, $deps;

    # The subset of %deps that are in @ARGV.
    $modules{$module} = +{ map { $deps{$_} ? ($_ => 1) : ()} @ARGV };
}

my @installation_order = map { prereqs $_ } keys %modules;

sub prereqs {
    my $module = shift;
    my $prereqs = $modules{$module};

    return +( map { prereqs $_ } keys %$prereqs ), $module;
}

say join " ", uniq @installation_order;