Hi, Perl Monks. I have this in file 'test.pl':

#!/usr/local/bin/perl
use strict;
use warnings;

use Player;
my $player = Player->new('vx' => -1);
for (keys %$player) {
        print "$_: ", $player->{$_}, $/;
}
[download]

which creates an object from Player.pm:

package Player;
use Mover;
@Player::ISA = qw(Mover);
use strict;

sub defaults {
        my $defaults = {
                'symbol'   => '_',
                'score'    => 0,
        }
}

1;
[download]

which inherits from Mover.pm:

package Mover;
use Object;
@Mover::ISA = qw(Object);
use strict;

sub defaults {
        my $defaults = {
                'symbol' => '?',     # override this in subclasses
                'x'      => 0,       # x-coordinate
                'y'      => 0,       # y-coordinate
                'vx'     => 0,       # velocity in x-direction
                'vy'     => 0,       # velocity in y-direction
                'shown'  => 1,       # still alive?
        }
}

1;
[download]

which in turn inherits from Object.pm:

package Object;
use strict;

sub new {
        my ($caller, %args) = @_;
        my ($self, $class);
        $class = ref $caller;
        $class ||= $caller;
        $self = bless {}, $class;
        $self->init(\%args);
        return $self;
}

sub init {
        my ($self, $args) = @_;
        my ($defaults);

        # See if superclass has defaults
        if ($self->can('SUPER::defaults')) {
                $defaults = $self->SUPER::defaults();
        }
        # Let current class override superclass
        if ($self->can('defaults')) {
                my $current_defaults = $self->defaults();
                for my $attr (keys %$current_defaults) {
                        $defaults->{$attr}
                             = $current_defaults->{$attr};
                }
        }
        # Set default values
        if (ref($defaults) eq 'HASH') {
                for my $attr (keys %$defaults) {
                        $self->{$attr} = $defaults->{$attr};
                }
        }
        # If %args are given to new(), use those instead
        for my $attr (keys %$args) {
                $self->{$attr} = $args->{$attr};
        }
}

1;
[download]

That's the subset of code that I've been using to try to isolate the problem. It's meant to be able to 1) inherit basic default "instance data" values from Mover.pm, 2) override some of those values in Player.pm, and finally 3) override both of those from the arguments passed to Player->new(). That's all done in the init() method of Object.pm.

The problem is, when I run 'test.pl', I get this:

$ ./test.pl
score: 0
vx: -1
symbol: _
[download]

That is, I only get 2) Player.pm defaults() and 3) new() args, while Mover.pm defaults() is never called. Thus, $self->can('SUPER::defaults') doesn't return "true". I've tried a very simple test case, and I found that the syntax of $self->can('SUPER::defaults') is correct. I can't figure out why it's not working in the code above, and I'm just going around in circles at this point. Please help?

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