Daily Use of PHP Factory Mode

The class or method responsible for generating other objects, this is the factory pattern, and the following is a common use

<?php
class test{
  public $x=1;
  public $setting;
  // Class or method responsible for generating other objects , This is the factory model 
  public function getSetting(){
    if(!$this->setting){
      $this->setting=new Setting();
    }
    return $this->setting;
  }
}
class Setting{
  public function __construct(){
    echo 1111;
  }
}
$test=new test();
$setting=$test->getSetting();
$setting2=$test->getSetting();
 
 
// Determine whether two objects are the same 1 Objects 
var_dump($setting===$setting2);
// Look at the number , You can also see that 
var_dump($setting);
var_dump($setting2);
 
 
 
 
// Handling with minus sign in attribute 
$name="x-b";
$test->$name=2;
 
var_dump($test);
 
 
//$test->x-b;// Use the above properties directly , Will be considered as 1 A minus sign 
/*
 Report an error :
PHP Notice: Use of undefined constant b - assumed 'b' in D:\phpServer\WWW\test\
test.php on line 11
 
Notice: Use of undefined constant b - assumed 'b' in D:\phpServer\WWW\test\test.
php on line 11
 
*/
 
echo $test->{'x-b'}; // This attribute contains - Such a package of 1 Under