protected function _pre($str) {
		$str=preg_replace('/(?<=^|\n)(?: {4}|\t)(.+?(?:\n+|$))/','\1',
			$this->esc($str));
		return strlen($str)?
			('<pre><code>'.
				$this->esc($this->snip($str)).
			'</code></pre>'."\n\n"):
			'';
	}
protected function _pre($str) {
		$str=preg_replace('/(?<=^|\n)(?: {4}|\t)(.+?(?:\n+|$))/','\1',
			$this->esc($str));
		return strlen($str)?
			('<pre><code>'.
				$this->esc($this->snip($str)).
			'</code></pre>'."\n\n"):
			'';
	}
protected function _pre ( $ str ) { $ str = preg_replace ( '/(?<=^|\n)(?: {4}|\t)(.+?(?:\n+|$))/' , '\1' , $ this -> esc ( $ str ) ) ; return strlen ( $ str ) ? ( '<pre><code>' . $ this -> esc ( $ this -> snip ( $ str ) ) . '</code></pre>' . "\n\n" ) : '' ; }
Process whitespace-prefixed code block
@return string
@param $str string
Process whitespace - prefixed code block