What is the purpose of enums in PHP?

In PHP, there is no built-in Enum type. However, Enum types can be simulated by creating class constants. Enums serve to define a set of named constants to better organize and manage code. Enums can make code more readable, easier to maintain, and help prevent the use of incorrect values.

For example, we can define an enumeration class to represent colors.

class Color {
    const RED = 'red';
    const BLUE = 'blue';
    const GREEN = 'green';
}

You can then use these enumerated values in the code as shown below:

$color = Color::RED;
switch ($color) {
    case Color::RED:
        echo "The color is red.";
        break;
    case Color::BLUE:
        echo "The color is blue.";
        break;
    case Color::GREEN:
        echo "The color is green.";
        break;
    default:
        echo "Unknown color.";
}

In this way, using enumerations can make the code clearer and easier to understand.