Analysis of new features of PHP8: How to use variable parameters and codes to simplify function calls?

Analysis of new features of PHP8: How to use variable parameters and codes to simplify function calls?

With the rapid development of technology, programming languages ​​are constantly updated and upgraded. As one of the most popular server-side scripting languages, PHP has introduced many exciting new features in its latest version, PHP8. Among them, variable parameters and code simplification functions are concerned and expected by the majority of developers.

1. Introduction of variable parameters

Variable parameters play a role in simplifying the code in function calls. It allows us to pass any number of parameters to the function without defining it. Specify the number of parameters in advance when using a function. In previous versions, PHP used functions such as func_num_args(), func_get_args(), and func_get_arg() to implement variable parameter processing. However, this approach is not concise and intuitive enough.

In PHP8, variadic parameters have been improved and optimized, we can now use the ... operator to specify variadic parameters in the function definition. For example, here is a simple example:

function sum(int ...$numbers): int {
    return array_sum($numbers);
}

echo sum(1, 2, 3, 4, 5);  // 输出：15

In the above example, ...$numbers represents variadic parameters, which allows us to pass any number of integers to the function sum(). Inside the function body, we can handle variable parameters $numbers just like normal arrays. In this way, we do not need to use additional functions to obtain and process variable parameters, which greatly simplifies the writing and reading of code.

In addition, variable parameters also support type declaration. For example, int ...$numbers in the example indicates that the variable parameter $numbers must be of integer type. If we try to pass a non-integer argument to function sum(), PHP will throw a type error at runtime.

2. Application of code simplification function

In addition to the introduction of variable parameters, PHP8 also provides some code simplification functions to help developers write function calls more efficiently. Among them, some of the most commonly used function calling methods, such as function calling, method calling and closure calling, have been simplified.

1. Function call

In previous versions, when we needed to call a global function, we needed to use call_user_func() or call_user_func_array()Function. In PHP8, we can directly use the function name to call it, which is very concise. For example:

function sayHello(string $name) {
    echo "Hello, {$name}!";
}

$function = 'sayHello';
$function('John');  // 输出：Hello, John!

In the above example, we assign the function name sayHello to the variable $function, and then directly call the variable to complete the function call. Compared with The previous approach greatly simplifies the code.

2. Method call

Before PHP8, we need to use the call_user_func()or call_user_func_array() function to call a Object methods. Now, we can use the callable syntax -> directly on the object, which is very intuitive. For example:

class Person {
    public function sayHello(string $name) {
        echo "Hello, {$name}!";
    }
}

$person = new Person();
$person->sayHello('John');  // 输出：Hello, John!

In the above example, we created an instance of the Person class and then directly called sayHello()# through -> ## method, the code is more concise and readable.

Closure call

() on closures without using the call_user_func() function. For example:

$greet = function (string $name) {
    echo "Hello, {$name}!";
};

$greet('John');  // 输出：Hello, John!

$greet, and then directly used () to call the closure, which is very concise and efficient.

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