<?php 
    // set a value for this example, but imagine the user 
    // was posting this in a form.
    $_POST['var1'] = 'another_type'; 
    
    $valueObj = new class($_POST['var1']) {
        private $m_value;
    
        public function __construct(string $input)
        {
            switch ($input)
            {
                case 'type1' : $this->m_value = 1; break;
                case 'type2' : $this->m_value = 2; break;
                case 'another_type' : $this->m_value = 3; break;
                default : throw new Exception("Invalid input: $input");
            }
        }
    
        public function getValue() : int { return $this->m_value; }
    };
    
    print $valueObj->getValue(); // 3
  

https://blog.programster.org/php7-0-anonymous-classes

I can't understand how $_POST['var1'] is assigned to $m_value inside the constructor.

CodePudding user response：

When object is created __construct function executes first. You have passed $_POST['var1'] while initialising object i.e new class($_POST['var1']) and in your constructor based on condition $this->m_value value is assigned, in your case it would be 3 as value is "another_type";

CodePudding user response：

$_POST['var'] isn't assigned to $m_value.

When the class is created, it is instantiated with the $_POST['var'] parameter, which is in turn passed to the __construct class constructor as $input.

The value of $input is then passed to the switch statement, which then assigns the value of 3 to $m_value.

Finally, $m_value is returned by the getValue() function.