preg_replace_callback question

[prokhaled]

I read this php code in site php.net

my question How can I know deep level ?


plain
>> DEB LEVEL=1

deep
>> >> DEB LEVEL=2

deeper


deep


plain






<?php
$input = "plain deep deeper deep plain";

function parseTagsRecursive($input)
{

$regex = '#\((?:[^[]|\[(?!/?indent])|(?R))+)\#';

if (is_array($input)) {
$input = '<div style="margin-left: 10px">'.$input[1].'</div>';
}

return preg_replace_callback($regex, 'parseTagsRecursive', $input);
}

$output = parseTagsRecursive($input);

echo $output;
?>