#!/usr/bin/perl
use strict;
use warnings;
use 5.010;
use Data::Dumper; $Data::Dumper::Sortkeys=1;

my $str1 = str::new('foo');
my $str2 = str::new('bar');

my $good1 = "$str1 $str2";
my $good2;
$good2 = $good1;
my($good3, $good4);
$good3 = "$str1 a";
$good4 = "a $str1";

my($bad1, $bad2, $bad3);
$bad1 = "a $str1 a";
$bad2 = "$str1 $str2";
$bad3 = "a $str1 a $str2 a";

say Dumper { GOOD => [$good1, $good2, $good3], BAD => [$bad1, $bad2, $bad3] };

$bad1 = ''."a $str1 a";
$bad2 = ''."$str1 $str2";
$bad3 = ''."a $str1 a $str2 a";
say Dumper { BAD_GOOD => [$bad1, $bad2, $bad3] };


package str;
use Data::Dumper; $Data::Dumper::Sortkeys=1;

use strict;
use warnings;
use 5.010;

use Scalar::Util 'reftype';

use overload (
    '""'        => \&stringify,
    '.'         => \&concat,
);

sub new {
    my($value) = @_;
    bless((ref $value ? $value : \$value), __PACKAGE__);
} 

sub stringify {
    my($str) = @_;
#say Dumper { stringify => \@_ };
    if (reftype($str) eq 'ARRAY') {
        return join '', @$str;
    }
    else {
        $$str;
    }
}

sub concat {
    my($s1, $s2, $inverted) = @_;
#say Dumper { concat => \@_ };
    return new( $inverted ? [$s2, $s1] : [$s1, $s2] );
}

1;