Creating chain methods in PHP, also known as method chaining, involves designing your classes in such a way that methods return the object itself ($this), allowing you to call multiple methods in a single statement. Here's a basic guide on how to implement method chaining:

1. Class Definition:

   • Start by defining a class.

   • Inside the class, create several methods that you want to chain.

2. Return $this in Methods:

   • In each method, perform the required operations.

   • At the end of the method, return $this. This is the key to method chaining.

3. Instantiate the Object:

   • Create an instance of the class.

4. Chain Methods:

   • Call the methods in a chained manner using the object.

Example

Here's an illustrative example:

class Car {
    private $speed = 0;
    private $color = 'red';

    // Method to set speed
    public function setSpeed($speed) {
        $this->speed = $speed;
        return $this; // Return $this for chaining
    }

    // Method to set color
    public function setColor($color) {
        $this->color = $color;
        return $this; // Return $this for chaining
    }

    // Method to display car info
    public function displayInfo() {
        echo "The car is {$this->color} and moving at {$this->speed} km/h.\n";
        return $this;
    }
}

// Create an instance and chain methods
$car = new Car();
$car->setSpeed(100)->setColor('blue')->displayInfo();

Notes:

• Return $this: The most important aspect of method chaining is returning $this at the end of each method. This returns the current object, allowing the next method in the chain to be called on it.

• Method Order: The order in which methods are chained matters. Each method call modifies the state of the object for the next method in the chain.

• Fluent Interface: This pattern is often referred to as a fluent interface, which is a method of creating object-oriented code that is more readable and expressive.

Method chaining can make your code more concise and readable, especially when setting multiple properties or configurations. However, it's important to use it judiciously, as overly long chains can become difficult to read and debug.