package StrNum;

use Exporter ();
@ISA = 'Exporter';
@EXPORT = qw(StrNum);  # unusual

use overload        (
        '<=>'   => \&spaceship,
        'cmp'   => \&spaceship,
        '""'    => \&stringify,
        'bool'  => \&boolify,
        '0+'    => \&numify,
        '+'     => \&concat,
        '*'     => \&repeat,
);

# constructor
sub StrNum($) { 
    my ($value) = @_; 
    return bless \$value; 
} 

sub stringify { ${ $_[0] } } 
sub numify    { ${ $_[0] } } 
sub boolify   { ${ $_[0] } } 

# providing <=> gives us <, ==, etc. for free.
sub spaceship { 
    my ($s1, $s2, $inverted) = @_;
    return $inverted ? $$s2 cmp $$s1 : $$s1 cmp $$s2;
} 

# this uses stringify
sub concat { 
    my ($s1, $s2, $inverted) = @_;
    return StrNum $inverted ? ($s2 . $s1) : ($s1 . $s2);
} 

# this uses stringify
sub repeat { 
    my ($s1, $s2, $inverted) = @_;
    return StrNum $inverted ? ($s2 x $s1) : ($s1 x $s2);
}

1;