Method chaining technique gives us ability to call several methods with only one PHP expression (in one go)

class Bill {
    public $dinner = 20;
    public $dessert = 5;
    public $drink = 3;
    
    public $bill = 0;
    
    public function dinner($count) {
        $this->bill += $count * $this->dinner;
        return $this;
    }
    public function dessert($count) {
        $this->bill += $count * $this->dessert;
        return $this;
    }
    public function drink($count) {
        $this->bill += $count * $this->drink;
        return $this;
    }
}

$bill = new Bill;

We can call several methods one by one and print the

$bill

:

$bill->dinner(3); 
$bill->dessert(2);
$bill->drink(1);
echo $bill->bill;

Or we can combine the above 4 expressions using method chaining. The result will be the same:

echo $bill->dinner(3)->dessert(2)->drink(1)->bill;