PHP 7 features and brief notes

PHP-7-New-Features.txt

Better performance - PHP 7 is twice as fast as PHP 5.6. Optimization 

Scalar type declarations - pass function params with variable type

function sum (int $a, int $b){
	
}
Return type declarations - mention the return variable type of a function

function sum ($a, $b): int{
	
}
combined comparison operator - <=>
compares two values return

-1 if left value is lesser 
0 is equals
1 left value is greater

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Null coalescing operator - ?? - returns first value if that exists and not NULL

$value = $user_value ?? $default_value;

echo $page_title ?? "My Cool PHP App";

$username = $_POST['username'] ?? 'guest';

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Anonymous classes - useful for throw away classes - just for one time use class
new class { ... }

$quick_deck = new class (52) {
	private $card_count;

	public function __constructor($num){
		$this->card_count = $num;
	}
}

+++

Array as constants

// Define constants in PHP
define('APP_VERSION','1.0'); // defined at run time

// PHP 5.3
const APP_VERSION = '1.0'; // defined at compile time - bit faster - cons - can't use conditionall value as its assigning in compile time

// PHP 5.6
const APP_DIRS = array('app','incl','lib');

// PHP 7
define('APP_DIRS', array('src','lib','vendor')); // allowed in PHP 7 but not in PHP 5

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Unicode codepoint escape syntax "\u{ codepoint }"
echo "\u{002764}"; // print black heart symbol
echo "\u{260F}"; // print telephone
echo "\u{1F600}";

+++

Uniform variable syntax - Evaluate dynamic variable names left to right

$name = 'car';
$car = array ('name' => 'Jetta', 'year' = > 2018);

echo $$name['name'];
// PHP 5: Warning: Illegal string offset 'name'
// Evaluated as ${$name['name']}

// PHP 7: Jetta
// Evaluated as ($$name)['name']

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cachable exceptions and syntax - no need to throw exceptions to catch errors

function hello_from($user) {
	return $user->say_hello();
}

try {
	echo hello_from(NULL);
} catch (Error $e) {
	echo "Rescued from: {$e->getMessage()}"; 
}

// PHP 7: Rescused from: call to a member function say_hello() on null

+++

PHP Error Hierarchy

Throwable
	Error
		ArithmeticError
			DivisionByZeroError
		AssertionError
		ParseError
		TypeError
	Exception
		LogicException
		RuntimeException
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Integer division with intdiv()

// PHP 7
echo intdiv(5,2);
// 2

// PHP 5 & earlier

echo (int)(5 / 2);

echo floor(5 / 2);

Modulus operator returns remainder

echo 5 % 2;
// 1

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Filtered unserialize() - unserialize($string, $options)

here $options = array('allowed_classes' => array('User'));

It has options to add additional params to either true or false to allowed_classes or array of allowed classes that can be serialized.

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Grouped imports with use():

Now, in PHP 7, we can use single use to add multiple files from a single directory

require_once('constants.php');
require_once('database.php');
require_once('plurals.php');

// PHP 5
use App\Library\Constants;
use App\Library\Database as DB;
use App\Library\Plurals;

// PHP 7
use App\Library\{Constants, Database as DB, Plurals};

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Other less frequently used features in PHP 7:

CSPRNG library - random_bytes() and random_int()
CSPRNG - Cryptographically Secure Sudo Random Number Generator

New IntlChar class provides utility functions for working with Unicode characters and codepoints

session_start() - accepts an array of options which overrides php.ini file configuration

Closure::call for binding and calling a closure

assert() - can throw custom exceptions; can configure to be ignored (e.g., in production)

preg_replace_callback_array() - similar to preg_replace_callback() but executed per pattern.

Generator::getReturn() - allows returning final value from a generator

Generators can delegate to other generators using yield from

New reflection classes - ReflectionGenerator and ReflectionType

New reflection methods in ReflectionParameter and ReflectionFunctionAbstract

+++

Deprecations and Deletions 

PHP 4 Constructors - The class and method has the same name

// old way of constructor function
Class User {
	public $name;

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

// new way of constructor function

Class User {
	public $name;

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

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Alternative PHP Tags:

<?php echo "PHP Tags"; ?> - Standard way - recommended

<% echo "ASP-style tags"; %> - removed in PHP 7

<%= "ASP-style tags with echo"; %> - turn on PHP parser and echo the output

<script language="php"> - removed in PHP 7
echo "Script-style tags";
</script>

// Does not change "short-open" tags

<? echo "Short-open tags"; ?>

<?= "Short-open tags with echo"; ?>

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Time Zone Warnings - removed

PHP 5: Date and time functions emit warnings if date.timezone is not set in php.ini; defaults to UTC

PHP 7: Date and time functions emit NO warnings if date.timezone is not set in php.ini; defaults to UTC

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PHP 5 Deprecations and removed completely in PHP 7:

All ereg_* functions; use preg_* instead

All mysql_* functions; use mysqli_* or OOP instead - deprecated since php 5.5.

Magic quotes functions

In PHP 7, you can no longer call non-static methods inside an object statically. This is really bad programming. These were deprecated in php 5.6.

set_socker_blocking

mcrypt_generic_end

mcrypt_ecb, mcrypt_cbc, mcrypt_cfb, mcrypt_ofb

datefmt_set_timezone_id