use 5.010;

use strict;
use warnings;

package InOutObj;

use Hash::Util::FieldHash 'fieldhash';

fieldhash my %upper;
fieldhash my %lower;

sub new {bless \do {my $dummy}, shift}
sub upper {$upper{$_[0]}}
sub lower {$lower{$_[0]}}
sub set {
    my ($self, $arg) = @_;
    $upper{$self} = uc $arg;
    $lower{$self} = lc $arg;
    $self;
}

package main;

my $obj = InOutObj->new;
$obj->set('i LiKe WiNe');

say $obj->upper;
say $obj->lower;

__END__
I LIKE WINE
i like wine