use strict;
use warnings;
use feature 'say';

use Data::Dump qw( pp );
my @strs =
  qw(
       "..\\"..
       "abc"
       "a\"bc"
       "a\\\\bc"
       "a\"
   );



my %re =
  (
   LanX => qr/ " (?> \\\\ | \\" | [^"] )* " /x,
   Eily => qr/ " (?: [^"\\] | \\. )* " /x,
   Poss => qr/ " (?: \\\\ | \\" | [^"] )*+ " /x,

  );


for my $str (@strs) {
   say "\nTesting: <$str> = ", pp ($str);
   $str =~ /$re{$_}/ and say "$_ found $&" or say "$_ found nothing"
     for keys %re;
}