/(?x:((?-x:)) # (comment)
  )/

##</code><code>##

  /((?-x:)) # (comment)
  /x

##</code><code>##

            else if (s[2] == '{' /* This should match regcomp.c */
                     || ((s[2] == 'p' || s[2] == '?') && s[3] == '{'))

##</code><code>##

  our $re_true = qr{(?=)}x;
  our $re_false = qr{(?!)}x;
  our $count;

  /
    # (?{ ... }) or (??{ ... }) or (legacy) (?p{ ... })
    \G \( \? (?: \? \?? | p ) (?= \{ )
    (?{ local $count = 0; })
    (?:
       \{ (?{ local $count = $count + 1 })
    |
       \} (?{ local $count = $count - 1 })
    |
       \\ .
    |
       .
    )+?
    (??{ $count == 0 ? $re_true : $re_false })
  /xgc;