use Regexp::SlashN;

"A
B
C" =~ /(\N+)/;

$1 eq "A
B
C" or die;

##</code><code>##

package Regexp::SlashN;
use overload;
sub import { overload::constant qr => \ &convert }

# A simple table of definitions
my %syntax = ( '\\' => '\\',
               N => '[^\n]', );

sub convert {
    my ( $re ) = @_;
    $re =~ s/\\([\\N])/$syntax{$1}/g;
    return $re;
}