Type hinting in PHP

Type hinting is a feature in PHP that allows a developer to specify the expected data type of a function argument or return value. It is a way to ensure type safety and prevent errors caused by passing arguments of the wrong type to a function or returning values of the wrong type from a function.

This is done by adding a type declaration to the function signature. This can be done for both function arguments and return values.

For example, to specify that a function expects an integer argument, we can use the int typehint like this:

function add(int $x, int $y): int {
    return $x + $y;
}

In this example, the add function takes two integer arguments and returns an integer value. The int typehint is used to specify the expected data type of the function arguments and return value.

Typehinting is optional in PHP, which means that you can still write functions without type declarations. However, using typehinting can help make your code more robust and easier to understand, especially in larger projects where there are many functions and collaborators.

PHP supports several data types for typehinting, including scalar types (int, float, bool, and string), array, object, and callable. You can also use nullable types by adding a question mark (?) before the type name to indicate that the argument or return value can be null.

function divide(?float $x, ?float $y): ?float {
    if ($y == 0) {
        return null;
    }
    return $x / $y;
}