use strict; use warnings; use feature qw( say ); use Data::Dumper qw( Dumper ); BEGIN { package str; use strict; use warnings; use feature qw( say ); use overload '""' => \&stringify, '.' => \&concat; sub new { my $class = shift; bless([ @_ ], $class) } sub stringify { join '', @{ $_[0] } } sub concat { my ($s1, $s2, $inverted) = @_; return ref($s1)->new( $inverted ? ($s2,$s1) : ($s1,$s2) ); } $INC{"str.pm"} = 1; } sub _dump { local $Data::Dumper::Indent = 0; local $Data::Dumper::Terse = 1; local $Data::Dumper::Sortkeys = 1; return Dumper(@_); } { my $str = str->new('foo'); my $good = "a $str a"; say "good: "._dump($good); my $bad; $bad = "a $str a"; say "bad: "._dump($bad); } #### good: bless( [bless( ['a ',bless( ['foo'], 'str' )], 'str' ),' a'], 'str' ) bad: 'a foo a'