Remove nested quotes

Question

I have this text and I\'m trying to remove all the inner quotes, just keeping one quoting level. The text inside a quote contains any characters, even line feeds, etc. Is th

Answer 1

You can use this:

$result = preg_replace('~\G(?!\A)(?>(\[quote\b[^]]*](?>[^[]+|\[(?!/?quote)|(?1))*\[/quote])|(?[^[]+|\[(?!/?quote))+\K)|\[quote\b[^]]*]\K~', '', $text);

details:

\G(?!\A)              # contiguous to a precedent match
(?>                   ## content inside "quote" tags at level 0
  (                    ## nested "quote" tags (group 1)
    \[quote\b[^]]*]
    (?>                ## content inside "quote" tags at any level
      [^[]+
     |                  # OR
      \[(?!/?quote)
     |                  # OR
      (?1)              # repeat the capture group 1 (recursive)
    )*
    \[/quote]
  )
 |
  (?              ## content that is not a quote tag
    [^[]+           # all that is not a [
   |                # OR
    \[(?!/?quote)   # a [ not followed by "quote" or "/quote"
  )+\K              # repeat 1 or more and reset the match
)
|                   # OR
\[quote\b[^]]*]\K   # "quote" tag at level 0