sort_by_attr_order_monkey_patch.pl

#!/usr/bin/perl -l

use strict;
use warnings;

use Mojo::Util;
use Mojo::Collection;

Mojo::Util::monkey_patch('Mojo::Collection', sort_by_attr_order => sub {
    my ($self, $attr, $order) = @_;

    my %order_map = map { $order->[$_] => $_ } 0..@{$order}-1;

    return $self->sort( sub { $order_map{$a->{$attr}} <=> $order_map{$b->{$attr}} } );
});

print Mojo::Collection->new               ( { a => 2 }, { a => 1 }, { a =>3 } )
                      ->sort_by_attr_order( a => [ 3, 2, 1 ] )
                      ->map               ( sub { $_->{a} } )
                      ->join              ( ', ' );

# 3, 2, 1