How can PHP developers maintain code readability when including multiple program parts from separate files?

To maintain code readability when including multiple program parts from separate files, PHP developers can use namespaces and proper file organization. By organizing related functions and classes into separate files and using namespaces to group them together, developers can easily locate and understand different parts of the codebase.

// File: functions.php
namespace MyNamespace;

function myFunction() {
    // Function implementation
}

// File: classes.php
namespace MyNamespace;

class MyClass {
    // Class implementation
}

// File: main.php
require_once 'functions.php';
require_once 'classes.php';

use MyNamespace;

// Code that uses the functions and classes
myFunction();
$obj = new MyClass();