I agree that the behaviors should be identical, though I don't understand why the pure-perl version uses that code versus the 0 + $object idiom.

use strict;
use warnings;
use Scalar::Util qw( refaddr );

sub refaddr_pp {
    return if not ref $_[0];
    return 0 + $_[0];
}

my $obj = bless {}, 'Foo';
my $ref = {};

print 'refaddr    $obj: ', refaddr($obj),    "\n";
print 'refaddr_pp $obj: ', refaddr_pp($obj), "\n\n";
print 'refaddr    $ref: ', refaddr($ref),    "\n";
print 'refaddr_pp $ref: ', refaddr_pp($ref), "\n";
[download]

Prints

refaddr    $obj: 149445664
refaddr_pp $obj: 149445664

refaddr    $ref: 149445904
refaddr    $ref: 149445904
[download]

I don't understand why the pure-perl version uses that code versus the 0 + $object idiom.

Because that idiom fails if $object overloads addition to do something else.

Because that idiom fails if $object overloads addition to do something else.

Doh! (Can you tell I don't mess with overloading much? Wasn't even on my radar screen.) OK, then, quick perusal of overload reveals the StrVal function, which can get us back to the original "grab the right substring and convert" approach without the reblessing.

use strict;
use warnings;
use Scalar::Util qw( refaddr );

package Foo;
use overload
    '0+'    => sub { 0 },
    q{""}   => sub { "Some Object" },
    fallback => 1;

package main;
use overload;

sub refaddr_pp {
    return if not ref $_[0];
    overload::StrVal($_[0]) =~ /0x(\w+)/;
    return hex $1;
}

my $obj = bless {}, 'Foo';
my $ref = {};

print 'stringify  $obj: ', "$obj",           "\n";
print 'refaddr    $obj: ', refaddr($obj),    "\n";
print 'refaddr_pp $obj: ', refaddr_pp($obj), "\n\n";
print 'stringify  $ref: ', "$ref",           "\n";
print 'refaddr    $ref: ', refaddr($ref),    "\n";
print 'refaddr_pp $ref: ', refaddr_pp($ref),    "\n\n";
[download]

Prints

stringify  $obj: Some Object
refaddr    $obj: 155892768
refaddr_pp $obj: 155892768

stringify  $ref: HASH(0x94abd10)
refaddr    $ref: 155893008
refaddr_pp $ref: 155893008
[download]

-xdg

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Wouldn't blessing a copy of the reference in order to extract the address work, and allow the blessed copy to be discarded leaving the original unmodified?

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?

"Science is about questioning the status quo. Questioning authority".

The "good enough" maybe good enough for the now, and perfection maybe unobtainable, but that should not preclude us from striving for perfection, when time, circumstance or desire allow.

Anyway, after reblessing the object, wouldn't it be better to take the reference in numeric context than to extract the number from the string form?