Operators allow you to change something about the Money and will return a new
instance of the Money. For example, the methods: add, subtract, multiply, and
divide on the
Money class are all MoneyOperators.
You can create your own Money Operators and use them with the Money class out of the box.
Here's how it works in slightly more detail.
<?php use SonsOfPHP\Component\Money\Operator\Money\AddMoneyOperator; use SonsOfPHP\Component\Money\Money; $accountBalance = Money::USD(1000); $depositAmount = Money::USD(2000); // The construct takes the deposit amount we will apply to the balance $operator = new AddMoneyOperator($depositAmount); // The operator will apply (the deposit amount) to the account balance // and the returned MoneyInterface will be a new object $newBalance = $operator->apply($accountBalance); $newBalance->isEqualTo($accountBalance); // will return false // Another way to use the Operator is $anotherNewBalance = $accountBalance->with($operator); $newBalance->isEqualTo($anotherNewBalance); // will return true // Even though $newBalance and $anotherNewBalance are different objects, they // are both USD and both have the same amount (3000)
As you can see, using Operators provides you some power. You could create your Operator to calculate a payment amount for a loan. Another great idea is to use an Operator that can calculate tax.