public static function FILTER_SANITIZE_TURTLE_STRING($value)
	{
		$value = preg_replace('/\\\\/', '\\\\\\\\', $value);	// escape backslash
		$value = preg_replace('/\r?\n|\r/', '\\n', $value);  // newline 
		$value = preg_replace('/"/', '\\"', $value);		// escape double quote
		
		return $value?:null;
	}
public static function FILTER_SANITIZE_TURTLE_STRING($value)
	{
		$value = preg_replace('/\\\\/', '\\\\\\\\', $value);	// escape backslash
		$value = preg_replace('/\r?\n|\r/', '\\n', $value);  // newline 
		$value = preg_replace('/"/', '\\"', $value);		// escape double quote
		
		return $value?:null;
	}
public static function FILTER_SANITIZE_TURTLE_STRING ( $ value ) { $ value = preg_replace ( '/\\\\/' , '\\\\\\\\' , $ value ) ; // escape backslash $ value = preg_replace ( '/\r?\n|\r/' , '\\n' , $ value ) ; // newline  $ value = preg_replace ( '/"/' , '\\"' , $ value ) ; // escape double quote return $ value ? : null ; }
escape double quotes, backslash and new line
empty allowed
escape double quotes backslash and new line empty allowed