# PHP Anonymous Functions (Closures)

Anonymous functions, also known as **closures**, allow the creation of functions which have no specified name. They are most often used as the value of callback parameters, but they have many other uses.

---

## 1. Basic Syntax
Anonymous functions are implemented using the `Closure` class.

```php
$greet = function($name) {
    echo "Hello " . $name;
};

$greet('World');
$greet('PHP');
```

## 2. Inheriting Variables from Parent Scope
Closures may also inherit variables from the parent scope. Any such variables must be passed to the `use` language construct.

```php
$message = 'hello';

// Inherit $message
$example = function () use ($message) {
    echo $message;
};
$example(); // Outputs: hello
```

## 3. Example: Callbacks
Anonymous functions are frequently used as callbacks for built-in array functions.

```php
$numbers = [1, 2, 3, 4];

$squared = array_map(function($n) {
    return $n * $n;
}, $numbers);

print_r($squared);
// Array ( [0] => 1 [1] => 4 [2] => 9 [3] => 16 )
```

[[programming/php/php]]