PHPのミュータブル

mutable.php

<?php
class GameManager {

 public function play()
    {
        $this->candidateWinnerPlayers = $this->players;
        while(!$this->getIsEnd()){
            echo "戦争!".PHP_EOL;
            $this->submitCardToField();
            $this->displayFieldCard();
            $this->judge();
        }

        $this->sortPlayersByScore();
        $this->displayRanking();

        echo "戦争を終了します。".PHP_EOL;
    }
}