How to use PHP7's type declarations to write more readable code?

How to use PHP7 type declarations to write more readable code?

With the release of PHP7, type declaration has become an important feature of PHP. Type declarations allow us to explicitly specify the data types of input parameters and return values ​​in functions and methods. This can effectively improve the readability and robustness of your code. In this article, we’ll cover how to use PHP7’s type declarations to write more readable code, and provide concrete code examples.

1. Parameter type declarations for functions and methods

In PHP7, we can use type declarations before the parameters of functions and methods to clearly specify the data type of the parameters. Doing this can help us understand more clearly what type of data the input parameters of a function or method should be.

For example, we have a function that calculates the sum of two integers:

function sum(int $a, int $b): int {
    return $a + $b;
}

In the above code, we use a type declaration to specify the two elements of the function sum The data types of the parameters $a and $b are integers. In this way, PHP will throw a fatal error when non-integer data is passed in.

2. Return value type declaration of functions and methods

In addition to parameter type declaration, we can also use type declaration after the colon of functions and methods to explicitly specify the return The data type of the value.

For example, we have a function that determines whether a number is even:

function isEven(int $num): bool {
    return ($num % 2 == 0);
}

In the above code, we use a type declaration to specify the return of the function isEven The data type of the value is Boolean. This way, PHP will throw a fatal error when the function returns a non-Boolean value.

3. Class attribute type declaration

In addition to parameter and return value type declarations for functions and methods, PHP7 also introduces class attribute type declarations. We can explicitly specify the data type of a property by using the keywords var and data type before the property's annotation.

For example, we have a class used to represent a person's information:

class Person {
    /** @var string */
    private $name;

    /** @var int */
    private $age;

    /** @var bool */
    private $isMale;

    public function __construct(string $name, int $age, bool $isMale) {
        $this->name = $name;
        $this->age = $age;
        $this->isMale = $isMale;
    }

    // ...
}

In the above code, we use comments and var keywords to specify the data of the attribute $name of the class Person The type is string, the data type of $age is integer, and the data type of $isMale is Boolean. In this way, when we use these attributes in other methods of the class, the IDE or editor will give corresponding type hints to help us understand the data types of the class attributes more clearly.

It should be noted that using attribute type declaration does not ensure that the actual data type of the attribute conforms to the declared data type. Therefore, we still need to verify and process data in the code to ensure the correctness of the data.

Through the above example, we can see that by using the type declaration of PHP7, we can clearly specify the data type of the parameter, the data type of the return value and the data type of the class attribute in the code, thereby improving Code readability and robustness.

Summary:

By properly using PHP7’s type declarations, we can write code with better readability. Type declarations can help us quickly understand the data types in the code, reduce the occurrence of errors, and provide more precise code prompts and automatic completion functions. However, it should be noted that type declaration does not completely guarantee the correctness of the data. We still need to verify and process the data. Therefore, in the process of writing code, we should make full use of the advantages of type declarations and combine them with other code specifications and best practices to improve the quality and readability of the code.

The above is the detailed content of How to use PHP7's type declarations to write more readable code?. For more information, please follow other related articles on the PHP Chinese website!