Recursive preg replace?

June 2, 2009

Hey there,

I'm trying to use some BB code, however, i'm having a porblem when it comes to using it recursively (e.g. a quote within a quote).

It works fine if there is just one [ quote][ /quote], but if it was to look like this: [ quote][ quote][ /quote][ /quote], only the first [ quote][ /quote] gets formatted. Is there any way to make my preg_replace recursive?

Here is the code:

		$input = nl2br(htmlspecialchars($input));
		$input = str_replace(array('\r\n', '\r', '\n'), '&lt;br /&gt;', $input);
		$find = array(  
			"'\[b\](.*?)\[/b\]'is",  
			"'\[i\](.*?)\[/i\]'is",  
			"'\[quote](.+)\[/quote\]'i",
		); 
		$replace = array(  
			"&lt;strong&gt;\\1&lt;/strong&gt;",
			"&lt;i&gt;\\1&lt;/i&gt;",
			"Quoting &lt;div class=\"quote\"&gt;\\1&lt;/div&gt;",
		); 
		$output = preg_replace($find, $replace, $input);

2,032 · June 2, 2009

Here's some code to mull over (just change {code} to [ code] and {/code} to [ /code] with a find/replace):

&lt;?php

$input = "[b]Hello[/b]\n\n{code}He said:{code}I'm here{/code}there{/code}\nBoo\n\n[quote]He said:[quote]I'm here[/quote]there[/quote]";

$input = nl2br(htmlspecialchars($input));
# Line break to br tag
$input = str_replace(array('\r\n', '\r', '\n'), '&lt;br /&gt;', $input);

# Non-recursive tags
$find = array(  
	"'\[b\](.*?)\[/b\]'is",
	"'\[i\](.*?)\[/i\]'is",
); 
$replace = array(  
	"&lt;strong&gt;\\1&lt;/strong&gt;",
	"&lt;i&gt;\\1&lt;/i&gt;",
); 
$output = preg_replace($find, $replace, $input);

# Function to handle recursive tags - not sure how to pass parameters :/
function BBParse($input)
	{
	global $tag, $fPre, $fPos, $regex;
	if (is_array($input)) $input = $fPre . $input[1] . $fPos;
	return preg_replace_callback($regex, 'BBParse', $input);
	}

# Recursive quotes
$tag = 'quote';
$fPre = '&lt;div style="border:1px solid red;padding:5px;"&gt;&lt;strong&gt;Quoting:&lt;/strong&gt;&lt;br /&gt;';
$fPos = '&lt;/div&gt;';
$regex = "#\[quote]((?:[^[]|\[(?!/?quote])|(?R))+)\[/quote]#i";
$output = BBParse($output);

# Recursive code tags
$tag = 'quote';
$fPre = '&lt;div style="border:1px solid blue;padding:5px;"&gt;&lt;strong&gt;Code:&lt;/strong&gt;&lt;br /&gt;';
$fPos = '&lt;/div&gt;';
$regex = "#\{code}((?:[^[]|\[(?!/?code])|(?R))+)\{/code}#i";
$output = BBParse($output);

echo $output;

?&gt;

If anyone knows how to pass parameters with preg_replace_callback then you don't need to set things up before calling it, just pass them as paramters. Otherwise it works, but is a little messy.

June 2, 2009

I've checked it, the code works fine when i've got it in a standalone php file, but as soon as I drop it into a class it stops working.

I'll have to take a look but thanks for your help!

2,842 · June 2, 2009

	private static function QuoteTag($string) {

		preg_match_all('/(?&lt;!\\\\)\[quote(?::\w+)?\]/i', $string, $quote_open);
		preg_match_all('/(?&lt;!\\\\)\[quote(?::\w+)?=(?:"|"|\')?(.*?)["\']?(?:"|"|\')?\]/i', $string, $quote_opens);
		preg_match_all('/(?&lt;!\\\\)\[\/quote(?::\w+)?\]/i', $string, $qe);

		$qopen = count($quote_open[0]) + count($quote_opens[0]);
		$qend = count($qe[0]);

			if ($qopen == $qend) {
				$string = str_replace('[quote]', '&lt;blockquote&gt;&lt;p&gt;', $string);
				$string = preg_replace('/(?&lt;!\\\\)\[quote(?::\w+)?=(?:"|"|\')?(.*?)["\']?(?:"|"|\')?\]/i', 
				"&lt;blockquote&gt;&lt;h3&gt;\\1&lt;/h3&gt;&lt;p&gt;", $string);
				$string = str_replace('[/quote]', '&lt;/p&gt;&lt;/blockquote&gt;', $string);
				$string = str_replace('[/QUOTE]', '&lt;/p&gt;&lt;/blockquote&gt;', $string);
			}
		return $string;
	}

if open tag count is the same as close tag count, then do quotes.

June 2, 2009

I'd rather not have a seperate class for just quotes, also, I wish to use a bit of regex (

hello

) so I cant use str_replace.

2,032 · June 2, 2009

It'll stop working in a class because of the "global $someVars" on the first line of the BBParse function. Global references outside a class.

For use in a class

&lt;?php

class BBHandler
	{
	private $tag;
	private $fPre;
	private $fPos;
	private $regex;

	public function Parse ($input)
		{
		# Basic parsing
		$output = $this-&gt;StraightParse($input);
		# Quote tags
		$this-&gt;tag = 'quote';
		$this-&gt;fPre = '&lt;div style="border:1px solid red;padding:5px;"&gt;&lt;strong&gt;Quoting:&lt;/strong&gt;&lt;br /&gt;';
		$this-&gt;fPos = '&lt;/div&gt;';
		$this-&gt;regex = "#\[quote]((?:[^[]|\[(?!/?quote])|(?R))+)\[/quote]#i";
		$output = $this-&gt;RecursiveParse($output);
		# Code tags
		$this-&gt;tag = 'code';
		$this-&gt;fPre = '&lt;div style="border:1px solid blue;padding:5px;"&gt;&lt;strong&gt;Code:&lt;/strong&gt;&lt;br /&gt;';
		$this-&gt;fPos = '&lt;/div&gt;';
		$this-&gt;regex = "#\{code}((?:[^[]|\[(?!/?code])|(?R))+)\{/code}#i";
		$output = $this-&gt;RecursiveParse($output);

		return $output;
		}

	private function StraightParse ($input)
		{
		$input = nl2br(htmlspecialchars($input));
		# Line break to br tag
		$input = str_replace(array('\r\n', '\r', '\n'), '&lt;br /&gt;', $input);

		# Non-recursive tags
		$find = array(  
			"'\[b\](.*?)\[/b\]'is",
			"'\[i\](.*?)\[/i\]'is",
		); 
		$replace = array(  
			"&lt;strong&gt;\\1&lt;/strong&gt;",
			"&lt;i&gt;\\1&lt;/i&gt;",
		); 
		$output = preg_replace($find, $replace, $input);
		return $output;
		}

	private function RecursiveParse ($input)
		{
		if (is_array($input)) $input = $this-&gt;fPre . $input[1] . $this-&gt;fPos;
		return preg_replace_callback($this-&gt;regex, array($this, 'RecursiveParse'), $input);
		}
	}

$BB = new BBHandler();

$input = "[b]Hello[/b]\n\n{code}He said:{code}I'm here{/code}there{/code}\nBoo\n\n[quote]He said:[quote]I'm here[/quote]there[/quote]";

echo '&lt;pre&gt;' . $BB-&gt;Parse($input) . '&lt;/pre&gt;';

?&gt;

June 2, 2009

That works perfectly! I've just extended it from my framework.

Quick question, with the regex, i'm a little stumped, I want to have

[ quote name=Harry time=12th feb 2009]this is his quote[/ quote]

So I thought i'd add that to the regex:

$this->regex = "#\[ quote name=(.*?) time=(.*?)]((?:[^[]|\[(?!/?quote])|(?R))+)\[/ quote]#i"; // i also added //1, //2 and changed //1 to 3.

Then I wanted to be able to have it as options, so you could use [ quote] or [ quote name=Harry], [ quote time=12th feb 2009] or a match of them all.

So I changed it to [ quote( name=(.*?))?( time=(.*?))?]((?:[^[]|\[(?!/?quote])|(?R))+)\[/ quote]

But I couldn't manage to get it to work. Any help would be great!

2,201 · June 3, 2009

Use BBCode

http://uk3.php.net/manual/en/intro.bbcode.php

This extension aims to help parse BBCode text in order to convert it to HTML or another markup language. It uses one pass parsing and provides great speed improvement over the common approach based on regular expressions. Further more, it helps provide valid HTML by reordering open / close tags and by automatically closing unclosed tags.
Since 0.10.1 It supports argument quoting with single quotes, double quotes and HTML escaped double quotes.

Regular expressions are horrible for this type of thing.

June 3, 2009

I really don't want to have to use anything other than pure php. That means i'd like to stay away from a user having to install BBCode on their server.

I did check that option out though, so thank you!

June 3, 2009

Is there any way to do what I explained two posts above? Cheers!

2,201 · June 3, 2009

If you insist.

\[quote(?:\s*?name=([a-zA-Z0-9]++))?(?:\s*?time=([a-zA-Z0-9\s]++))?]((?:[^[]++|\[(?!\/quote]))+)\[\/quote]

[quote name=Harry time=12th feb 2009]this is his quote[/quote]

Group 1: Harry

Group 2: 12th feb 2009

Group 3: this is his quote

if (preg_match('%\[quote(?:\s*?name=([a-zA-Z0-9]++))?(?:\s*?time=([a-zA-Z0-9\s]++))?\]((?:[^[]++|\[(?!\/quote\]))+)\[\/quote\]%si', $subject))
{
	# Successful match
}
else
{
	# Match attempt failed
}

February 6, 2020

thanks @Popcorned1.

1,844 · February 8, 2020

On 2/6/2020 at 7:01 AM, PRSBOY said:

thanks @Popcorned1.

...11 years later xD

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