PHP 7 – A look at the future

by Radu Murzea

25 July 2015

Agenda

A bit of History

Most important new features of PHP 7 Mini-demo of each one

Q&A

PHP – A bit of high-level historyPHP < 5

1995 - 2008

PHP with most known

features

Zend Engine 1

PHP – A bit of high-level historyPHP < 5

1995 - 2008 2004 - 2017

PHP 5

PHP with most known

features

Zend Engine 1

Zend Engine 2

NewObject-Oriented

Model

PHP – A bit of high-level historyPHP < 5

1995 - 2008 2004 - 2017 2015 - ?

PHP 5 PHP 7

PHP with most known

features

Zend Engine 1

Zend Engine 2

Zend Engine 3

NewObject-Oriented

Model Keep reading

AST-based CompilationSeparation of parser and compiler

Higher Maintainability Decouple syntax issues from technical issues

Performance Improvement

Usually 10 – 20 % faster But requires more memory

Removes many syntax limitations

See “Uniform Variable Syntax” Chapter

Reference

https://wiki.php.net/rfc/abstract_syntax_tree

AST looks

like this

Uniform Variable SyntaxConsistent left-to-right variable dereferencing

Stuff like this is now possible:

$foo['bar']->baz->oof()::$rab explode(‘|’, $x)[3] $foo()[‘bar’]() foo()() (function() { return 1+2+3; })() ‘Foo’::$bar

Reference

https://wiki.php.net/rfc/uniform_variable_syntax

Return Type Declarations (I)Motivation

Prevent unintended return values Document return type in a way that is not easily removed (like phpdoc

comments)

Rules

In case of inheritance -> invariant enforcement If return type is declared, NULL may not be returned Not allowed on __construct(), __destruct() and __clone()

Multiple return types are NOT allowed

Return Type Declarations (II)

Reference

https://wiki.php.net/rfc/return_types

Example

class MyClass { function a() { //return type is optional return 123; } function b(): int { //fatal error - "int" doesn't exist return 123; } function c(): ClassB { //fatal error - can't return null here return null; }}

Anonymous Classes (I)Motivation

Anonymous classes are frequently used in other languages (Java, C#)

Basic Rules

Instantiating requires providing values to constructor arguments Inheritance and Traits works just like for named classes Attempting to serialize will result in an ERROR

Use Cases

In very simple cases, where dedicated file + class-doc = overkill When it’s small + you need it only once during execution When you don’t want to hit the autoloader for extremely simple classes Primitive support for situations where inner classes would make sense

Reference

https://wiki.php.net/rfc/anonymous_classes

Anonymous Classes (II)Examples

$x = new class(123) { public function __construct($a) { $this->a = $a; }};

(new class extends SomeClass implements SomeInterface { public function init() { /* ... */ }})->doStuff();

class MyClass extends MyOtherClass { public function getInstance() { return new class implements MyInt { /* ... */ }; }}

Many Fatal Errors become ExceptionsMotivation

Execution immediately aborted, cannot be recovered from finally blocks or __destructor() s are not called

Solution

Reference

https://wiki.php.net/rfc/engine_exceptions_for_php7 https://wiki.php.net/rfc/throwable-interface https://trowski.com/2015/06/24/throwable-exceptions-and-errors-in-php7/

Context Sensitive LexerMotivation

PHP reserved words prevent good/natural API designs

Example

This is now possible:

Finder::for(‘project’) ->where(‘name’)->like(‘%secret%’) ->and(‘priority’, ‘>’, 9) ->or(‘code’)->in([‘4’, ‘5’, ‘7’]) ->and()->not(‘created_at’)->between([$t1, $t2]) ->list($limit, $offset);

Reference

https://wiki.php.net/rfc/context_sensitive_lexer

Grouping Use Declarations (I)Motivation

Cut verbosity when importing classes, functions or constants Easier to identify which entities belong to the same module

Reference

https://wiki.php.net/rfc/group_use_declarations

Example

This:

use Foo\Bar\StuffA;use Foo\Bar\StuffB as MyB;

becomes this:

use Foo\Bar\{ StuffA, StuffB as MyB};

Null Coalesce OperatorMotivation

Operations like “if data exists, use it; otherwise use default” are quite cumbersome to do

Description/Examples

Denoted by ?? Returns result of 1st operand if it exists and is not NULL; otherwise

returns 2nd operand The following 2 statements are equivalent:

$a = isset($_GET[‘a’]) ? $_GET[‘a’] : ‘default’;

$a = $_GET[‘a’] ?? ‘default’; The following 2 statements are equivalent as well:

if (($a = A::$value) === null) { $a = $default; }

$a = A::$value ?? $default;Reference

https://wiki.php.net/rfc/isset_ternary

Unicode Code Point Escape SyntaxMotivation

Proper escape syntax for Unicode characters Support for more than 16-bit-length BPM characters Syntax is \u{xxxxxx} – with variable length

Examples

echo "\u{202E}Right-to-left text";will print: txet tfel-ot-thgiR

echo “\u{1F602}”; //Emoji – Face with Tears of Joywill print:

Reference

https://wiki.php.net/rfc/unicode_escape

Performance – MediaWiki – Requests/s

Source: http://talks.php.net/velocity15#/mwbench

Performance – Wordpress - Latency

Source: http://talks.php.net/velocity15#/wpbench

Q & A