BBcode class vil ikke virke

PHP kode 

 $str = preg_replace(array(
     '/[b](.*)[\/b]/is',
      /[i](.*)[\/i]/is'
 ),array
      '<b>$1</b>',
      '<i>$1</i>'
 ),$str);

Kode 

<?php
class format {
	var $text;
	function text($text)
	{
		$this->text = $text;
		$this->text = htmlspecialchars($this->text);
		$this->text = htmlentities($this->text);
		$linebreaks = array("\r\n", "\n\r", "\n", "\r");
		$this->text = str_replace($linebreaks, "<br />", $this->text);
		$this->text = preg_replace_callback('/\[(b|i|u|quote)\](.*)\[\/\1\]/Umi',
                                        create_function('$tag','
		switch ($tag[1]) 
		{
		case "b": 
			return "<b>{$tag[2]}</b>";
		case "i": 
			return "<i>{$tag[2]}</i>";
		case "u": 
			return "<u>{$tag[2]}</u>";
		case "quote":
			return "<blockquote>{$tag[2]}</blockquote>";
		case "code":
			return "<div class=\"code\">" . highlight_string(html_entity_decode($tag[2]), true) . "</div>";
		}
                                        '), $this->text);
		return $this->text;
	}
}


$f=new format();

print($f->text("
[b]fed tekst[/b]
[i]kursiv tekst[/i]
[u]understreget tekst[/u]
"));
?>

Kode 

class format
{
	public $text;
	public function bbcode($starttag, $content, $endtag) 
	{
		if (strcasecmp($starttag, $endtag) != 0) 
		{
        	return $content;
        	}
		switch ($starttag) 
		{
		case 'b': 
			return "<b>{$content}</b>";
			break;
		case 'i': 
			return "<i>{$content}</i>";
			break;
		case 'u': 
			return "<u>{$content}</u>";
			break;
		case 'quote':
			return "<blockquote>{$content}</blockquote>";
			break;
		case 'code':
			$content = preg_replace("(<br />)", "\n", $content);
			$content = highlight_string(html_entity_decode($content), true);
			return "<div class=\"code\">{$content}</div>";
			break;
		}
	}
	public function url($url,$link)
	{
		$url = trim($url);
		if((strcasecmp(substr($url,0,7), "http://") == 0) || (strcasecmp(substr($url,0,4), "www.") == 0)){
			return "<a href=\"{$url}\" target=\"_blank\">{$link}</a>";
		} else {
			return "<a href=\"http://{$url}\" target=\"_blank\">{$link}</a>";
		}
	}
	public function text($text)
	{
		$this->text = $text;
		$this->text = htmlentities($this->text);
		$this->text = preg_replace("(\n)", "<br />", $this->text);
		$this->text = preg_replace("#\[([a-zA-Z]+)\](.+)\[/([a-zA-Z]+)\]#Ues", "\$this->bbcode(\"$1\",'\\2',\"$3\")", $this->text);
		$this->text = preg_replace("#\[url=(.+)\](.+)\[/url\]#e", "\$this->url(\"$1\",\"$2\")", $this->text);
		return $this->text;
	}