Most objects in Perl are blessed hash references but not all.

Since any kind of reference can be blessed it depends on the implementation, if and how you can "see inside". (That's particularly difficult for inside/out objects.)

Good news, it's Perl, i.e. the implementation is open to be read.

Thank you for that link to Ovid's .perldb. Useful additions to my own, described here if you are interested: http://blogs.perl.org/users/matthew_persico/2016/12/saving-breakpoints-in-the-perl-debugger.html.

Nope,

$ perl -MIO::All -MData::Printer -e " p( io(2) ); "
Can't use string ("") as a symbol ref while "strict refs" in use at ..
+./site/lib/Data/Printer.pm line 702.
[download]

Thanks, that's right. Its because io() will emit an overloaded object so stringification would trigger.

You'll have to "peel off" the overloading, so to speak, by invoking overload::Overloaded (though funny, the perldoc says this should "true if 'arg' is subject to overloading...", wasn't expecting an actual GLOB object there.)

% perl -de 0 -MIO::All -MData::Printer

Loading DB routines from perl5db.pl version 1.51
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

main::(-e:1):    0
  DB<1> $io = io '.zshrc'

  DB<2> x overload::Overloaded( $io )
0  GLOB(0x17a4378)
   -> *IO::All::((
  DB<3> $o = overload::Overloaded( $io )

  DB<4> Data::Printer::p($o)
\ *IO::All::((  (layers: )

  DB<5>
[download]

It would probably make a nice exercise to implement a Data::Printer filter for this.

Example

$ perl -de 1

Loading DB routines from perl5db.pl version 1.37
Editor support available.

Enter h or 'h h' for help, or 'perldoc perldebug' for more help.

main::(-e:1):   1
  DB<1> x use IO::All; use Data::Dump::Streamer; sub dd { Dump(@_); ()
+; }
0  0
  DB<2> x our $banana = io('2.txt');
0  IO::All::File=GLOB(0x16af5fc)
   ->
  DB<3> x dd $banana
my ($class,$constructor,%flags,@flags);
$class = 'IO::All';
$constructor = sub {
                 package IO::All::Base;
                 use warnings;
                 use strict;
                 my $self = $class->new(@_);
                 foreach $_ (@flags) {
                   $self->$_($flags{$_});
                 }
                 $self->constructor($constructor);
                 return $self;
               };
%flags = ();
@flags = ();
$IO_All_File1 = do{ require Symbol; Symbol::gensym };
*$IO_All_File1 = {
                   _assert     => 0,
                   _autoclose  => 1,
                   _binary     => undef,
                   _binmode    => undef,
                   _encoding   => undef,
                   _lock       => 0,
                   constructor => $constructor,
                   io_handle   => undef,
                   is_open     => 0,
                   mode        => undef,
                   name        => '2.txt',
                   package     => 'IO::All',
                   tied_file   => undef
                 };
bless( $IO_All_File1, 'IO::All::File' );
  empty array
  DB<4> q

$
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Wow. Such a lesson. Thanks.

I haven't tried it out but why do you write x dd ... if your dd() just returns an empty list ?

dd() seems to do all the writing already.

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!}