package SomeClass;

use overload 
    '<>' => \&diamond;
    
sub diamond
{ 
    my $self = shift;
    
    if ( wantarray )
    {
        print "wants array\n";
        return $self->handle->getlines;
    }
    else
    {
        print "wants scalar\n";
        return $self->handle->getline;
    }
    
}

#... rest of code