PHP da OOP da interfeyslarning bir-biridan meros olishi

Interfeyslar, xuddi klasslar kabi, extends operatori yordamida bir-biridan meros olishlari mumkin. Keling, buni bir misol orqali ko'rib chiqaylik. Faraz qilaylik, bizda oldingi darsdagı shunday bir interfeys mavjud:

php<?php
  interface iRectangle
  {
    public function __construct($a, $b);
    public function getSquare();
    public function getPerimeter();
  }
?>

Biroq, bizda iFigure interfeysi allaqachon mavjud bo'lib, u bizning interfeysimizning bir qism metodlarini tavsiflaydi:

iFigure.php<?php
  interface iFigure
  {
    public function getSquare();
    public function getPerimeter();
  }
?>

Keling, iRectangle interfeysi iFigure interfeysining metodlaridan meros olsin:

iRectangle.php<?php
  interface iRectangle extends iFigure
  {
    public function __construct($a, $b);
  }
?>