Re: Moose 'clone' Constructor

[choroba]

Note that there can't be a general cloning routine free to use in all the cases. Imagine each object has a temp file created somewhere - when cloning an object, do you want it to share the same file(handle)? What if each object registers itself to a static hash or a parent object, generates a unique ID, seeds a PRNG, etc?

#! /usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

{   package MyObj;
    use Moose;

    has fh => (is => 'ro', builder => '_build_fh');

    sub _build_fh {
        my ($self) = @_;
        open my $fh, '>', "/tmp/$self" or die $!;
        return $fh
    }

    sub DEMOLISH {
        my ($self) = @_;
        close $self->fh;
        unlink "/tmp/$self";
    }
}

my $o = 'MyObj'->new;

{
    my $c = $o->meta->clone_object($o);
}

say { $o->fh } "Hello world!";  # say() on closed filehandle $fh

[kcott]

G'day choroba,

++ That's a very valid point; thanks for raising it. It even applies to the code I'm currently working with, which I paraphrased for this post as:

my $cloned_object = ref($existing_object)->new();

As I indicated in the OP, I want an object that's of the same class as $existing_object, but I want default values (not whatever values $existing_object has). In fact, if I had taken $existing_object's values, that would've broken my code in all sorts of interesting ways.