php7.md

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PHP 7	February 19, 2016	/articles/php-7/	https://raw.githubusercontent.com/php-earth/php-resources-assets/master/images/introduction/php7.png

Introduction

PHP 7 is the next major version of the PHP language. You really should check it out and upgrade.

Why PHP 7 and not PHP 6?

Choosing the version 7 (instead of 6) was chosen because a lot of existing books were mentioning PHP 6 long before the development of the next major version after PHP 5 started. Andi Gutmans said "We're going to skip version 6 because years ago, we had plans for a 6 but those plans were very different from what we're doing now," so the name PHP 7 was chosen.

Major changes

Most important changes from PHP 5:

• Performance improvements - PHP 7 is significantly faster than previous versions.
• Exceptions in the engine
• Scalar type declarations
• Combined comparison (spaceship) operator
• Easy user-land CSPRNG
• Null coalescing operator
• Removed deprecated functionality from PHP 5

Be sure to read more about the changes in the migration chapter of PHP manual.

Exceptions in the engine

In previous versions you couldn't catch fatal errors. Now you can do this:

<?php

function doSomething($obj) {
    $obj->nope();
}

try {
    doSomething(null)
} catch (\Error $e) {
    echo "Error: {$e->getMessage()}\n";
}

// Error: Call to a member function method() on a non-object

Scalar type declarations

Now you can enforce parameter types as strings (string), integers (int), floating-point numbers (float), and booleans (bool). Type declarations (previously known as type hints) in PHP 5 were class names, interfaces, array and callable.

<?php

// Coercive mode
function sum (int ...$numbers) {
    return array_sum($numbers);
}

var_dump(sum(2, '3', 4.1)); // outputs 9

Besides coercive mode there is also strict mode which can be enabled per file basis with:

<?php

declare(strict_types=1);

Read more about type declarations in the PHP manual.

Combined comparison (spaceship) operator

The spaceship operator is used for three-way comparison of two expressions. It returns:

• 1 (if the left-hand operand is greater than the right-hand operand)
• 0 (if both operands are equal)
• -1 (if the right-hand operand is greater than the left-hand operand)

Example of spaceship operator where you need to sort multidimensional array

To do this, you can use usort() with comparison function:

<?php

$items = [
    ['title' => 'Mouse'],
    ['title' => 'Computer'],
    ['title' => 'LCD Screen'],
];

// sort items by title
usort($items, function ($a, $b) {
    return $a['title'] <=> $b['title'];
});

Easy user-land CSPRNG

PHP 7 has two new functions random_bytes() and random_int() for generating cryptographically secure integers and strings in a cross platform way.

Before PHP 7 you had to use the generator on the platform. For example, CryptGenRandom on Windows and /dev/urandom on Linux. If you're building modules that must work on all platforms, this might be an issue. In PHP 7 you can simply use the built-in generator.

Null coalescing operator

It turned out that often you needed to use ternary operator with isset() function.

An example where you need to check if the GET data has been sent and set the $username based on that. In PHP 5 you could do something like this:

<?php
$user = isset($_GET['user']) ? $_GET['user'] : 'Guest';

Now you can simplify this a lot:

<?php
$user = $_GET['user'] ?? 'Guest';

Resources

Other resources and tutorials to get to know and use PHP 7:

• Rasmus Lerdorf's PHP 7 development box - Debian Vagrant box with PHP 7 installed.
• PHP 7 Docker container - Docker container with PHP 7.
• PHP 7 logo - PHP 7 logo by Vincent Pontier and Peter Cowburn.
• php7cc - PHP 7 Compatibility Checker.
• Reading:
  • Getting ready for PHP 7
  • PHP 7 Reference - An overview of the features, changes, and backward compatibility breakages in PHP 7.
  • PHP 7 tutorial - Interactive simple and efficient tutorial presenting all the important changes and backwards incompatibilities.