Online PHP editor | output for jcr8p

<?php abstract class TestClass { public static $currentValue; public static function toValue($value) { self::$currentValue = $value; return __CLASS__; } public static function add($value) { self::$currentValue = self::$currentValue + $value; return __CLASS__; } public static function subtract($value) { self::$currentValue = self::$currentValue - $value; return __CLASS__; } public static function result() { return self::$currentValue; } } $value = TestClass::toValue(5)::add(3)::result(); echo $value;