sub dequote {
   my ($s) = @_;
   if ($s =~ /^"/) {
      $s =~ s/^"//;
      $s =~ s/"$//;
   }
   $s =~ s/\\(.)/$1/sg;
   return $s;
}

      my $val = /\G
         (
            " (?: [^\\"] | \\. )* "
         |
            (?: [^\\,] | \\. )*
         )
      /xsgc && dequote("$1");