PHP preg replace with newlines and recursive backreference

[beaulm]

I have kind of a complicated php preg_replace question.
I would like to change the word "pattern" if it appears in this following sequence:

pattern ( OR [ OR { any text ); OR ]; OR };

But only when it appears inside <-- --> and only with the entire rest of the pattern. Also, the any text has to be able to handle new lines. Here's an example.

I would like to turn this:

 <--
 pattern (some text);
 pattern [some more text];
 pattern {some text
 with a new line in it};
 pattern don't match this
 pattern [or this]
 pattern [or this
 pattern or this];
 -->
 
 pattern (don't match this either);
 pattern and definitely not this!
 
 <--
 pattern [but you can
 match this];
 -->

Into

 <--
 pineapple (some text);
 pineapple [some more text];
 pineapple {some text
 with a new line in it};
 pattern don't match this
 pattern [or this]
 pattern [or this
 pattern or this];
 -->
 
 pattern (don't match this either);
 pattern and definitely not this!
 
 <--
 pineapple [but you can
 match this];
 -->

So far the code I have to this looks like:

 <?php
 $text='<--
 pattern (some text);
 pattern [some more text];
 pattern {some text
 with a new line in it};
 pattern dont match this
 pattern [or this]
 pattern [or this
 pattern or this];
 -->
 
 pattern (dont match this either);
 pattern and definitely not this!
 
 <--
 pattern [but you can
 match this];
 -->';
 $output=preg_replace('@(<--.*?)pattern ([(\[{])(.*?)(\);¦];¦};){1}(.*?-->)@s','$1pineapple $2$3$4$5',$text);
 echo $output;
 ?>

But that only changes the first patterns in the first block and the second block. I tried putting the preg_replace in a while loop that went until it didn't match any patterns--which worked until I tried putting it into development where I got some really crazy problems. I actually need this functionality for a more complex project, unfortunately I'm unable to divulge the details of it :(

If anyone has anything that might be able to help I'd really appreciate it! I'm not a regular expressions expert by any means so I'd really love to learn how to do this right.

[edited by: eelixduppy at 11:33 pm (utc) on July 10, 2009]
[edit reason] disabled smileys [/edit]

[eelixduppy]

This is what I came up with real quick. It's probably not complete but it should certainly get you off the ground. :)

function callback($matches) 
{ 
    $match_string = 'pattern'; 
    $replace_string = 'pineapple'; 

    $pattern = '/'.preg_quote($match_string).'\s([\[{(]([^\[\]{}()](?!'.preg_quote($match_string).'))*[\]})];)/'; 

  return preg_replace($pattern, "$replace_string \\1", $matches[0]); 
} 

/* Grab all of the text between the two tags <-- and --> */ 
$pattern = '/<--[^->]*-->/'; 
echo '<pre>'.preg_replace_callback($pattern, 'callback', $text).'</pre>'; 

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