Potential tpl:format, untested

gistfile1.aw

	protected static $format_types = array();

	public function tpl_format(ToxgBuilder $builder, $type, array $attributes, ToxgToken $token)
	{
		$this->requireEmpty($token);
		$this->requireAttributes(array('value', 'as'), $attributes, $token);

		$value = $builder->parseExpression('normal', $attributes['value'], $token);
		$as = preg_replace('~[^a-z_-]~', '', strtolower($attributes['as']));

		// Pass it off to the format handler
		if (array_key_exists($as, self::$format_types))
			call_user_func(self::$format_types[$as], $builder, $type, $attributes, $token);
		// !!! Should there be a default output here? Maybe just emit what's in $value?
	}

	public static function addFormatType($name, $callback)
	{
		$name = preg_replace('~[^a-z_-]~', '', strtolower($name));

		// Only allow one callback per format type, and make sure it's callable
		if (!empty($name) && is_callable($callback))
			self::$format_types[$name] = $callback;
	}

	public static function removeFormatType($name)
	{
		$name = preg_replace('~[^a-z_-]~', '', strtolower($name));

		if (array_key_exists($name, self::$format_types))
			unset(self::$format_types[$name]);
	}

	public static function getFormatTypes()
	{
		return self::$format_types;
	}