Atomic grouping (?>...) seems to fix the problem 
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

  );


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

[download]

Testing: <"..\"..> = "\"..\\\".."
LanX found nothing
Eily found nothing

Testing: <"abc"> = "\"abc\""
LanX found "abc"
Eily found "abc"

Testing: <"a\"bc"> = "\"a\\\"bc\""
LanX found "a\"bc"
Eily found "a\"bc"

Testing: <"a\\bc"> = "\"a\\\\bc\""
LanX found "a\\bc"
Eily found "a\\bc"

Testing: <"a\"> = "\"a\\\""
LanX found nothing
Eily found nothing

[download]

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!

In reply to Re^9: Parser Performance Question (Atomic grouping) by LanX
in thread Parser Performance Question by songmaster

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