PHP 7

About Me

• Cloud Engineer at Datto
• Zend Certified
• Linux user for 14 years
• I like Elephants

What's New?

• Scalar Type Hints
• Return Types
• Combined Comparisons <=>
• Null Coalescing ??
• Anonymous Classes
• Cleaner Use Declarations
• Improved Performance
• One or two things broke as well

Scalar Type Hints

• PHP 7 supports scalars (int, float, bool, string) for type hinting
• Works just like Class/Interface type hinting

                        <?php
function addIntegers(int $a, int $b)
{
    return $a + $b;
}
var_dump(addIntegers(5, 10)); // int(15)
                    

• PHP is still a loosely-typed language

Scalar Type Hints

• Type juggling will cast types when possible

                        <?php
function addIntegers(int $a, int $b)
{
    return $a + $b;
}
var_dump(addIntegers(5.0, '10')); // still int(15)
                    

• Unless you tell it not to

                        <?php
declare(strict_types=1);

function addIntegers(int $a, int $b)
{
    return $a + $b;
}
var_dump(addIntegers(5.0, '10')); // TypeError thrown
                    

Scalar Type Hints

A few caveats for strict mode:

• The strict_types declaration must be enabled for each file
• Has to be the first statement
• Deviating will throw a FatalError

                        <?php
function addAnything($a, $b)
{
    return $a + $b;
}

declare(strict_types=1); // BAD! - FatalError thrown
function addIntegers(int $a, int $b)
{
    return $a + $b;
}
var_dump(addIntegers(5, 10));
                    

Return Types

• Similar to Type Hinting
• Allows declaration of the return type
• Scalars, Interfaces, Classes and Arrays permitted

                        <?php
function addIntegers(int $a, int $b): int
{
        return $a + $b;
}
var_dump(addIntegers(5, 10));
                    

Return Types

A few caveats for return types:

• Null not permitted! Will throw a FatalError
• Specifying a return type and deviating will throw a TypeError

                        <?php
function addIntegers(int $a, int $b): null // FatalError
{
    return $a + $b;
}

function addIntegersToo(int $a, int $b): int
{
    return 'This is not an integer'; // TypeError
}
                    

Combined Comparison Operator

• Also known as the spaceship operator
• DRYer comparison code

(value1) <=> (value2);

Combined Comparison Operator

• Returns 0 if both sides equal
• Returns 1 if left is greater
• Returns -1 if right is greater

                        <?php
var_dump(5 <=> 5); // 0
var_dump(10 <=> 5); // 1
var_dump(5 <=> 10); // -1
                    

Combined Comparison Operator

                        <?php
$distros = [
            ['name' => 'Debian', 'coolFactor' => 1876],
            ['name' => 'Mint', 'coolFactor' => 3059],
            ['name' => 'Ubuntu', 'coolFactor' => 1535],
            ['name' => 'Arch', 'coolFactor' => 738],
            ['name' => 'Fedora', 'coolFactor' => 1136]
];

usort($distros, function ($a, $b) { // the old way
    if ($a['name'] == $b['name']) {
        return 0;
    }
    return ($a['name'] < $b['name']) ? -1 : 1;
});

usort($distros, function ($a, $b) { // new hotness
    return $a['name'] <=> $b['name'];
});
                        

(We used arrays because a mock class didn't fit on one slide...)

Null Coalesce Operator

• Similar to the ternary operator
• Operates on values which could be null
• DRYer isset()s!

A practical example

                        <?php
// the old way
if (isset($_GET['page']) {
    $location = $_GET['page']; // abbreviated example, please avoid doing this
} else {
    $location = 'index';
}

// new hotness
$location = $_GET['page'] ?? 'index';
                    

Anonymous Classes

• stdClass has been around forever
• Not very flexible however
  • Not able to inherit other classes
  • Or implement interfaces
  • Methods need to be assigned via closures
• Enter Anonymous Classes
  • Perfect for one-off objects
  • Or quick implementations of small interfaces
  • Makes mocking tests a breeze

Anonymous Classes

                        <?php
require 'LinuxDistroInterface.php'; // tricky getting this to fit on one slide!
function processDistro(LinuxDistro $distro)
{
        echo $distro->getDistroName() . ' rocks!';
}

processDistro(new class('Debian') implements LinuxDistro {
    protected $name;

    public function __construct($name)
    {
        $this->name = $name;
    }

    public function getDistroName()
    {
        return $this->name;
    }
}); // Debian rocks!
                    

Group Use Declarations

• Libraries with many nested namespaces can be a pain
• PHP 7 provides shorter, DRYer uses via grouping

                                <?php
require './vendor/autoload.php';

use \Foo\Bar\Baz;
use \Foo\Bar\Biz;
use \Foo\Bar\Buz as Buzz;

$baz = new Baz;
$biz = new Biz;
$buz = new Buzz;
                            

                                <?php
require './vendor/autoload.php';

use \Foo\Bar\{ Baz, Biz, Buz as Buzz };

$baz = new Baz;
$biz = new Biz;
$buz = new Buzz;
                            

Improved Performance

• PHP 7 is significantly faster
• Some benchmarks show a 100% increase in performance
• Tons of low-level optimizations (zval simplified, allocator improved)
• Benchmarks - http://talks.php.net/fluent15
• Detailed explanation of the improved parser - http://www.slideshare.net/nikita_ppv/php-7-what-changed-internally-php-barcelona-2015

A couple of things broke..

Uniform Variable Syntax - everything is now evaluated left-to-right

                        <?php
$$foo['bar']['baz'];     // 5: ${$foo['bar']['baz']}    7: ($$foo)['bar']['baz']
$foo->$bar['baz'];       // 5: $foo->{$bar['baz']}      7: ($foo->$bar)['baz']
$foo->$bar['baz']();     // 5: $foo->{$bar['baz']}()    7: ($foo->$bar)['baz']()
Foo::$bar['baz']();      // 5: Foo::{$bar['baz']}()     7: (Foo::$bar)['baz']()
                    

TL;DR: Stop trying to be clever with variable-variables

A couple of things broke..

Errors are now thrown like Exceptions

• You can catch them
• Errors !== Exceptions however
• New base interface: Throwable

                        <?php
function ShouldReturnADataBaseHandle()
{
    return null;
}

try {
    $db = ShouldReturnADataBaseHandle();
    $stmt = $db->prepare('SELECT * FROM users'); // FatalError in 5.6
} catch (Throwable $t) {
    echo "Oops, something went wrong: {$t->getMessage()}";
}
                    

A couple of things broke..

ASP and <script> tag support dropped

                        <% echo 'Hello World'; %> // invalid
<%= 'Hello World'; %> // invalid
<script language="php"> echo 'Hello World'; </script> // invalid
                    

Short tags still work though

                        <?= 'Hello World'; ?>
<? echo 'Hello World'; ?> // only if short_open_tag is set to On in php.ini
                    

A couple of things broke..

• php.ini no longer supports # comments
• Deprecated since 5.4!
• Use ; for comments
• Affects all php-parsed ini files
• including parse_ini_file() & parse_ini_string()

Useful References

• Migration guide - http://php.net/manual/en/migration70.php
• https://www.digitalocean.com/company/blog/getting-ready-for-php-7/
• https://wiki.php.net/rfc/remove_deprecated_functionality_in_php7
• https://nikic.github.io/2015/05/05/Internal-value-representation-in-PHP-7-part-1.html

Questions?

Vagrantfile with some demos:

https://gitlab.com/zbtnot/php7-demo

Maps to 127.0.0.1:8080
vagrant ssh and cd /vagrant/cli-demos for some others