#!/usr/bin/perl --
use strict;
use warnings;
use Data::Dumper ();
Main( @ARGV );
exit( 0 );
sub Main {
    my $root = {
 'foo' => {
     'child1' => { 
          'gchild1' => {
              'values' => {
                   'bar1' => 1,
                   'bar2' => 1
                  }
             }
         },
     'child2' => {
          'gchild1' => {
              'values' => {
                   'bar1' => 1,
                   'bar2' => 1
                  }
             },
          'gchild2' => {
              'values' => {
                   'bar1' => 1,
                   'bar2' => 1
                  }
             }
         },
     'child3' => {
          'values' => {
             'bar1' => 1,
             'bar2' => 1
              }
         }
     }
    };


    use Data::Visitor::Callback;
    my $vorp = sub {
        my @v;
        my $v = Data::Visitor::Callback->new(
            ignore_return_values => 1,
            hash_entry => sub {
                my ( $self, $k, $v ) = @_;
                push @v, $v if $k eq 'values' and $v;
                return;
            },
        );
        $v->visit( @_ );
        return @v;
    };
    print DD( $root, [ $vorp->( $root ) ], ), '#' x 33 , "\n";

    use Data::Walk();
    $vorp = sub {
        my @v;
        Data::Walk::walk( sub {
## same result as 2nd if block below
#~             no warnings 'uninitialized';
#~             if( 'HASH' eq $Data::Walk::type and ref $_){
#~                 my $v = $_->{values};
#~                 push @v, $v if $v;
#~             }
            if( $_ eq 'values'){
                push @v, $Data::Walk::container->{values};
            }
            return;
        }, @_ );
        return @v;
    };
    print DD( $root, [ $vorp->( $root ) ], ), '#' x 33 , "\n";
}

sub DD { scalar Data::Dumper->new( \@_ )->Indent(1)->Useqq(1)->Dump; }
__END__

$VAR1 = {
  "foo" => {
    "child2" => {
      "gchild2" => {
        "values" => {
          "bar1" => 1,
          "bar2" => 1
        }
      },
      "gchild1" => {
        "values" => {
          "bar1" => 1,
          "bar2" => 1
        }
      }
    },
    "child3" => {
      "values" => {
        "bar1" => 1,
        "bar2" => 1
      }
    },
    "child1" => {
      "gchild1" => {
        "values" => {
          "bar1" => 1,
          "bar2" => 1
        }
      }
    }
  }
};
$VAR2 = [
  $VAR1->{"foo"}{"child2"}{"gchild2"}{"values"},
  $VAR1->{"foo"}{"child2"}{"gchild1"}{"values"},
  $VAR1->{"foo"}{"child3"}{"values"},
  $VAR1->{"foo"}{"child1"}{"gchild1"}{"values"}
];
#################################
$VAR1 = {
  "foo" => {
    "child2" => {
      "gchild2" => {
        "values" => {
          "bar1" => 1,
          "bar2" => 1
        }
      },
      "gchild1" => {
        "values" => {
          "bar1" => 1,
          "bar2" => 1
        }
      }
    },
    "child3" => {
      "values" => {
        "bar1" => 1,
        "bar2" => 1
      }
    },
    "child1" => {
      "gchild1" => {
        "values" => {
          "bar1" => 1,
          "bar2" => 1
        }
      }
    }
  }
};
$VAR2 = [
  $VAR1->{"foo"}{"child2"}{"gchild2"}{"values"},
  $VAR1->{"foo"}{"child2"}{"gchild1"}{"values"},
  $VAR1->{"foo"}{"child3"}{"values"},
  $VAR1->{"foo"}{"child1"}{"gchild1"}{"values"}
];
#################################