http://qs1969.pair.com?node_id=1114523

Minions is yet another OOP automation module, roughly similar to Moo, but which has the addtional goal of putting Encapsulation centre stage. I wrote it because after reading How Large Does Your Project Have To Be to Justify Using Moose? (especially the comments by tye and JavaFan), I became increasingly disillusioned with the Moo(se) way of OOP (essentially OOP with no Encapsulation).

Here is a sample that implements the fixed size queue from Re^5: The future of Perl? (that sub-thread also illustrates limitations of the Moo way of OOP)
package FixedSizeQueue; use Minions interface => [qw( push pop size )], construct_with => { max_items => { assert => { positive_int => sub { $_[0] =~ /^\d+$/ && $_[0 +] > 0 } }, }, }, implementation => 'FixedSizeQueue::Default', ; 1; package FixedSizeQueue::Default; use Minions::Implementation has => { q => { default => sub { [ ] } }, max_size => { init_arg => 'max_items', }, }, ; sub size { my ($self) = @_; scalar @{ $self->{$__q} }; } sub push { my ($self, $val) = @_; log_info($self); push @{ $self->{$__q} }, $val; if ($self->size > $self->{$__max_size}) { $self->pop; } } sub pop { my ($self) = @_; log_info($self); shift @{ $self->{$__q} }; } sub log_info { my ($self) = @_; warn sprintf "[%s] I have %d element(s)\n", scalar(localtime), $se +lf->size; } 1;
And a sample of usage:
% reply -I lib 0> use FixedSizeQueue 1> my $q = FixedSizeQueue->new(max_items => 3) $res[0] = bless( { '932db126-' => 'FixedSizeQueue::__Private', '932db126-max_size' => 3, '932db126-q' => [] }, 'FixedSizeQueue::__Minions' ) 2> $q->can $res[1] = [ 'pop', 'push', 'size' ] 3> $q->push($_) for 1 .. 3 [Mon Jan 26 12:01:53 2015] I have 0 element(s) [Mon Jan 26 12:01:53 2015] I have 1 element(s) [Mon Jan 26 12:01:53 2015] I have 2 element(s) $res[2] = '' 4> $q->pop [Mon Jan 26 12:02:09 2015] I have 3 element(s) $res[3] = 1 5> $q $res[4] = bless( { '932db126-' => 'FixedSizeQueue::__Private', '932db126-max_size' => 3, '932db126-q' => [ 2, 3 ] }, 'FixedSizeQueue::__Minions' ) 6> $q->push($_) for 4 .. 6 [Mon Jan 26 12:02:55 2015] I have 2 element(s) [Mon Jan 26 12:02:55 2015] I have 3 element(s) [Mon Jan 26 12:02:55 2015] I have 4 element(s) [Mon Jan 26 12:02:55 2015] I have 3 element(s) [Mon Jan 26 12:02:55 2015] I have 4 element(s) $res[5] = '' 7> $q $res[6] = bless( { '932db126-' => 'FixedSizeQueue::__Private', '932db126-max_size' => 3, '932db126-q' => [ 4, 5, 6 ] }, 'FixedSizeQueue::__Minions' ) 8> $q->log_info() Can't locate object method "log_info" via package "FixedSizeQueue::__M +inions" at reply input line 1. 9>
Not all Moo features are supported (for this early release I've focused on those I actually use). Important differences from Moo include
  1. Attributes can be safely accessed inside classes without the overhead of a function call
  2. As a consequence of 1., attributes need not be exposed via methods (unless there is a good reason to do so).
  3. No need to clean up animal droppings
  4. Private subroutines via the mechanism shown in Re: OO - best way to have protected methods (packages)
  5. Class methods are "class only", and object methods are "object only"
  6. No compatibility with Moose
Feedback is much appreciated.