Possible to have a :required attribute?

[srchulo]

I find the :ro attribute super useful. I often want to use :ro and have all fields be required, too. Would it be possible to add this as an attribute?

[tobyink]

This seems like a reasonable request.

Attributes could be made non-required by explicitly specifying required => false or by providing a default.

[srchulo]

Would this require changes to MooseX::MungeHas to support this?

[tobyink]

That would be the simplest way to implement it, yes.

[tobyink]

Released a new MooseX::MungeHas.

[srchulo]

Wow! That was fast :)

[tobyink]

It was only a few lines of code. The test cases were more work than the implementation.

Moops just needs this now:

use v5.14;
use strict;
use warnings FATAL => 'all';
no warnings qw(void once uninitialized numeric);

package Moops::TraitFor::Keyword::req;

our $AUTHORITY = 'cpan:TOBYINK';
our $VERSION   = '0.036';

use Moo::Role;

around arguments_for_moosex_mungehas => sub {
    my $next = shift;
    my $self = shift;
    require MooseX::MungeHas;
    MooseX::MungeHas->VERSION('0.011');
    return ('always_required', $self->$next(@_));
};

1;

Once you've got that, you should be able to do:

use Moops;

class Foo :req {
    ...;
}

I'll try to get it included in a release of Moops some time this month. If you wanted to write some test cases for it, that might help me get it released faster. t/94trait-ro-rw-rwp.t is pretty close to the kinds of tests you'd want to do.

[srchulo]

Thank you! I'm on vacation without my laptop now, but I will try to get to this soon to help you out :)

[srchulo]

Created pull request here:

https://github.com/tobyink/p5-moops/pull/7

Sorry-- I'm not sure if there's a better way to link these.

[srchulo]

Also, if you don't mind, could you explain how

return ('always_required', $self->$next(@_));

Works? It's returning 'always_required' and the values return by $next, but to what? And with multiple traits do the return values just stack up, and $next can be another around method for another trait? It looks like they're passed to use MooseX::MungeHas qw().

[tobyink]

Moops::Keyword::Role line 51-52 is:

push @lines, "use MooseX::MungeHas qw(@{[ $self->arguments_for_moosex_mungehas ]});"
    if $using =~ /^Mo/;

And Moops::Keyword::Role->arguments_for_moosex_mungehas just provides a list of strings.

Traits like :req get applied to Moops::Keyword::Role, so can modify the list returned by arguments_for_moosex_mungehas, in this case adding another string to it.

[srchulo]

Thank you for taking the time to explain this to me-- I'm trying to learn how Moops works and I appreciate it.

One more follow up question, when you have multiple traits like :req and :ro, are both arounds for arguments_for_moosex_mungehas called?

[tobyink]

Yep. That's just generally how around works in Moose/Mouse/Moo. Multiple roles can be applied to a class and can all use around to modify the same method. (The order in which they are applied is not guaranteed, but in this case, the order doesn't matter anyway.)

[srchulo]

Awesome, thank you :) Please let me know if you'd like any changes on the pull request :)

[tobyink]

Looks good to me.