PHP-verzögertes Teilen von statischen Bindungsbeispielen

<?php
class A {
 protected static $def = &#39;123456&#39;;
 
 public static function test() {
  echo get_class(new static);
 }
 
 public static function test2() {
  echo static::$def;
 }
}
 
class B extends A {
 protected static $def = &#39;456789&#39;;
}
 
class C extends A {
 protected static $def = &#39;abcdef&#39;;
}
 
echo B::test();
echo &#39;<br>&#39;;
echo C::test();
echo &#39;<br>&#39;;
echo B::test2();
echo &#39;<br>&#39;;
echo C::test2();
echo &#39;<br>&#39;;
echo A::test();
echo &#39;<br>&#39;;
echo A::test2();
echo &#39;<br>&#39;;

// 输出结果
B
C
456789
abcdef
A
123456