__invoke for callable objects in PHP - Mini Project: Build & Apply

__invoke for callable objects in PHP

📖 Scenario: Imagine you want to create a simple calculator object that can be called like a function to add two numbers.

🎯 Goal: You will build a PHP class with the __invoke magic method so that an object of this class can be used as a callable to add two numbers.

📋 What You'll Learn

Create a class named Adder

Add a __invoke method to the Adder class that takes two parameters

The __invoke method should return the sum of the two parameters

Create an object of the Adder class named adder

Call the adder object with two numbers and print the result

💡 Why This Matters

🌍 Real World

Using <code>__invoke</code> lets you create objects that act like functions, which can make your code cleaner and more flexible.

💼 Career

Understanding magic methods like <code>__invoke</code> is useful for PHP developers working on frameworks or libraries that use callable objects.

1

Create the Adder class

Create a class called Adder with no methods or properties.

PHP

<?php

// Create the Adder class
// Your code here

Need a hint?

Use the class keyword followed by Adder and curly braces.

2

Add the __invoke method

Inside the Adder class, add a public method named __invoke that takes two parameters named $a and $b.

PHP

<?php

class Adder {
    // Add the __invoke method with parameters $a and $b
    // Your code here
}

Need a hint?

Define a public function named __invoke with parameters $a and $b.

3

Return the sum inside __invoke

Inside the __invoke method, return the sum of $a and $b using the return statement.

PHP

<?php

class Adder {
    public function __invoke($a, $b) {
        // Return the sum of $a and $b
        // Your code here
    }
}

Need a hint?

Use return $a + $b; to send back the sum.

4

Create object and call it like a function

Create an object named adder from the Adder class. Then call adder with the numbers 5 and 7 and print the result using echo.

PHP

<?php

class Adder {
    public function __invoke($a, $b) {
        return $a + $b;
    }
}

// Create the adder object
// Call adder with 5 and 7 and print the result
// Your code here

Need a hint?

Create the object with new Adder(), then call it like a function with (5, 7), and print with echo.