function validateEmail($value) {
		//not too long to fit in the property? 
		$error = $this->validateString($value);
		if ($error) return $error;

		if ($value === null) return null;

		//requires @ with at least one character before, checks the domain name 
		//not allowing address literals nor comments 
		if (!preg_match('/^.+' //you may use '/^(?:"(?:\\\\.|[^"])*"|[^ ]+)' if you do not want to  allow whitespace outside double quoted
			. "@[\w0-9\-.]+\.\w{2,4}$/" //allows subdomains and numers. "@[\w-]+(\.\w{2,3})*\.\w{2,4}