Re: Moose stringification overloading isn't working

[Anonymous Monk]

Your output has two different classes in it:

Zep is              OT::Zeppelin::AddVendorKey 
stringifies as      OT::Zeppelin::AddVendorKey….
_stringify returns  OT::DB::Result::Upload...

So it looks like the line $this->row->ID can return two different objects.

The 'use overload' docs say:

The subroutines for '""' , '0+' , and 'bool' can return any arbitrary Perl *value*. If the corresponding operation for this *value* is overloaded too, the operation will be called again with this *value*.

As a special case if the overload returns the object itself then it will be used directly. An overloaded conversion returning the object is probably a bug, because you're likely to get something that looks like YourPackage=HASH(0x8172b34) .

Based on the order of the output, I would say that $this->row->ID is returning $this in some cases, and in other cases it is returning an object of the class OT::DB::Result::Upload, and that class has also overloaded '""'.

Here is a simple example of that:

use strict;
use warnings;
use 5.012;

##############
{
    package Point;
    use Moose; # automatically turns on strict and warnings

    has 'x' => (is => 'rw', isa => 'Int');
    has 'y' => (is => 'rw', isa => 'Int');

    use overload
        '""' => \&_stringify;

    sub _stringify {
        state $count;
        my ($rhs, $_lhs, $swap) = @_;

        $count++;

        if ($count < 2) {
            return $rhs;
        }
        else {
            return D->new;
        }
    }

}

################

{
    package Point3D;
    use Moose;
    extends 'Point';

    has 'z' => (is => 'rw', isa => 'Int');
}

###############

{
    package D; use Moose; 
    use overload
        '""' => sub {
                        my $class = ref shift;
                        return "$class|hello"
                    };


}
###############

my $p3d = Point3D->new(x=>10, y=>20);
say "$p3d";
say $p3d->_stringify;


--output:--
Point3D=HASH(0x100bc5078)
D|hello

[7stud]

What happens if you use double quotes twice? And what happens if you call _stringify() twice? Any difference?