What is an anonymous function in PHP?

An anonymous function in PHP is indeed a function without a name that can be assigned to a variable. This feature, often referred to as a closure or lambda, allows developers to create functions dynamically and pass them as arguments or store them in data structures.

The ability to assign an anonymous function to a variable makes it useful for various programming patterns, such as callbacks, event handling, or functional programming techniques. By using anonymous functions, developers can write more concise and flexible code, allowing for a high level of abstraction and code reusability.

While other choices describe different types of functions or behaviors, they do not accurately define what an anonymous function is. For example, the idea that a function cannot return a value is incorrect; anonymous functions can return values just like named functions. A function defined inside another function is known as a nested function, which is different from being anonymous. Lastly, suggesting that an anonymous function only runs once overlooks its ability to be invoked multiple times or passed to other functions. Thus, the description of an anonymous function as a nameless function assigned to a variable is the most accurate definition.