Any +/- feedback on Mouse?

Let me first say that Mouse is a stop-gap measure for people and situations where Moose is just not appropriate, such as:

• Vanilla CGI scripts
• Command Line apps that need fast startup
• Low resource environments (minimal memory and/or minimal CPU)
• Restricted deployment environments (hard to get modules installed, etc)

It should be noted that Mouse and Moose are about tied for runtime performance (if all the proper optimizations are applied) so unless your requirements match those listed above there is no sizable runtime performance boost you get from Mouse over Moose.

I will agree with your point that Moose is heavyweight, but the many dependencies is a typically overstated issue. If you have an environment where you can install modules, then what is the difference between typing install Moose vs. install Mouse?

Do we have any recent feedback on whether Moose will become a part of Perl core in a upcoming Perl release?

The problem with becoming "core" is that it freezes your module in time; bugs, issues and all. Moose is still being actively developed and improved upon and so needs a much more frequent releases then "core" could provide. If we were to put it into "core" the result would not really have much benefit if a user still needed to upgrade Moose from CPAN. Additionally, if you "core" Moose, then you would also need to core all it's dependencies as well, which means the same problems I described for Moose would then be taken on by these other modules.

In short, making a module "core" is not really a good thing so one that I would be resistant to (unless, as chromatic has suggested, the core Perl release schedule is radically changed and becomes much more frequent).

package M1;


use Mouse;

has 'x' => (is => 'rw');
has 'y' => (ks => 'rw');

1;

use M1;

my $m = M1->new(x => 55);

warn $m->x;

$m->x(888);

warn $m->x;
[download]

By default Moose (and I'd assume also Mouse) will allow you to pass any keys you want to an object constructor. So what happens is just that the ks is being ignored. The reason it doesn't throw an error for an unknown key is so you can do something like this:

package Foo;
use Moose;

has 'number' => (
    is    => 'rw',
    isa   => 'Num',
);

sub BUILD {
    my ( $self, $args ) = @_;
    $self->number( $args->{ 'foo' } * 42 );
}
[download]

You can turn this behavior off for your own modules with MooseX::StrictConstructor.

---

www.jasonkohles.com
We're not surrounded, we're in a target-rich environment!