Editing PHP (section)

=== PHP 8 ===
PHP&nbsp;8 was released on 26 November 2020, and is currently the second-most used PHP major version. PHP&nbsp;8 is a major version and has breaking changes from previous versions.<ref name="Brent">{{cite web |author=Brent |title=What's new in PHP 8 |url=https://stitcher.io/blog/new-in-php-8 |website=Stitcher |access-date=22 September 2020}}</ref><ref name="PHP">{{cite web |title=PHP 8 Released|url=https://www.php.net/releases/8.0/en.php |website=PHP |access-date=27 November 2020}}</ref> New features and notable changes include:

==== Just-in-time compilation ====
[[Just-in-time compilation]] is supported in PHP&nbsp;8.<ref name="wiki.php.net-2" />

PHP 8's [[just-in-time compilation|JIT compiler]] can provide substantial performance improvements for some use cases,<ref name="Brent-2">{{cite web |author=Brent |title=PHP 8: JIT performance in real-life web applications |url=https://stitcher.io/blog/jit-in-real-life-web-applications |website=Stitcher.io |access-date=4 October 2020}}</ref><ref>{{cite web |last1=Rethams |first1=Derick |title=PHP 8: A Quick Look at JIT |url=https://derickrethans.nl/a-quick-look-at-jit.html}}</ref> while (then PHP) developer Nikita Popov stated that the performance improvements for most websites will be less substantial than the upgrade from PHP&nbsp;5 to PHP&nbsp;7.<ref name="Popov-2020" /> Substantial improvements are expected more for mathematical-type operations than for common web-development use cases.<ref name="Popov-2020">{{cite web |last1=Popov |first1=Nikita |title="What's new in PHP 8.0?" Nikita Popov |date=13 July 2020 |url=https://www.youtube.com/watch?v=NbBRXwu1Md8  |archive-url=https://ghostarchive.org/varchive/youtube/20211211/NbBRXwu1Md8| archive-date=2021-12-11 |url-status=live|publisher=PHP fwdays |access-date=4 October 2020}}{{cbignore}}</ref> Additionally, the JIT compiler provides the future potential to move some code from C to PHP, due to the performance improvements for some use cases.<ref name="Daniele-2020">{{cite web |last1=Daniele |first1=Carlo |title=What's New in PHP 8 (Features, Improvements, and the JIT Compiler) |url=https://kinsta.com/blog/php-8/ |website=Kinsta |date=25 May 2020 |access-date=24 December 2020}}</ref>

==== Addition of the match expression ====
{{Main|PHP syntax and semantics#Match expression}}

PHP 8 introduced the {{code|match}} expression.<ref name="Redmond-2020">{{cite web |last1=Redmond |first1=Paul |title=Match Expression is Coming to PHP 8 |url=https://laravel-news.com/match-expression-php-8 |website=Laravel News |date=15 July 2020 |access-date=4 October 2020}}</ref> The match expression is conceptually similar to a {{code|switch}} statement and is more compact for some use cases.<ref name="PHP Watch">{{cite web |title=PHP 8.0: Match Expressions |url=https://php.watch/versions/8.0/match-expression |website=PHP Watch |access-date=4 October 2020}}</ref> Because {{code|match}} is an expression, its result can be assigned to a variable or returned from a function.<ref>{{cite web |last1=Barnes |first1=Eric |title=PHP 8 is now Released! |url=https://laravel-news.com/php-8 |website=Laravel News |date=27 November 2020 |access-date=24 December 2020 |ref=laravel-news-php-8-released}}</ref>

==== Type changes and additions ====
PHP 8 introduced union types, a new {{code|static}} return type, and a new {{code|mixed}} type.<ref name="Brent" />

"Attributes", often referred to as "annotations" in other programming languages, were added in PHP&nbsp;8, which allow metadata to be added to classes.<ref name="Brent" />

{{code|throw}} was changed from being a statement to being an expression.<ref name="wiki.php.net-4" /> This allows exceptions to be thrown in places that were not previously possible.<ref name="Brent" />

==== Syntax changes and additions ====
PHP&nbsp;8 includes changes to allow alternate, more concise, or more consistent syntaxes in a number of scenarios. For example, the nullsafe operator is similar to the [[null coalescing operator]] {{code|??}}, but used when calling methods.<ref name="wiki.php.net" /> The following code snippet will not throw an error if {{code|getBirthday()}} returns null:

<syntaxhighlight lang="php">
$human_readable_date = $user->getBirthday()?->diffForHumans();
</syntaxhighlight>

Constructor property promotion has been added as "[[syntactic sugar]]," allowing class properties to be set automatically when parameters are passed into a class [[Constructor (object-oriented programming)|constructor]].<ref name="Brent" /> This reduces the amount of [[boilerplate code]] that must be written.<ref>{{cite web |last1=Roose |first1=Brent |title=PHP 8: Constructor property promotion |url=https://stitcher.io/blog/constructor-promotion-in-php-8 |access-date=30 April 2024}}</ref>

Other minor changes include support for use of {{code|::class}} on objects, which serves as an alternative for the use of {{code|get_class()}};<ref name="Brent" /> non-capturing catches in try-catch blocks; variable syntax tweaks to resolve inconsistencies; support for named arguments; and support for trailing commas in parameter lists, which adds consistency with support for trailing commas in other contexts, such as in arrays.<ref name="PHP" />

==== Standard library changes and additions ====
* Weak maps were added in PHP&nbsp;8. A {{code|WeakMap}} holds references to objects, but these references do not prevent such objects from being [[Garbage collection (computer science)|garbage collected]].<ref name="wiki.php.net-3" /> This can provide performance improvements in scenarios where data is being [[Cache (computing)|cached]]; this is of particular relevance for [[object–relational mapping]]s (ORM).<ref name="Brent" />
* Various adjustments to interfaces, such as adding support for creating {{code|DateTime}} objects from interfaces, and the addition of a {{code|Stringable}} interface that can be used for type hinting.<ref name="Brent" />
* Various new functions including {{code|lang=php|str_contains()}}, {{code|lang=php|str_starts_with()}}, and {{code|lang=php|str_ends_with()}};<ref name="Merchant-2020">{{cite web |last1=Merchant |first1=Amit |title=These new string functions are coming in PHP 8 |url=https://www.amitmerchant.com/new-string-functions-php8/ |website=Amit Merchant |date=13 June 2020 |access-date=4 October 2020}}</ref> {{code|lang=php|fdiv()}}; {{code|lang=php|get_debug_type()}}; and {{code|lang=php|get_resource_id()}}<ref name="Brent" />
* Object implementation of {{code|lang=php|token_get_all()}}<ref name="Brent" />

==== Additional changes ====
* Type annotations were also added into PHP's C source code itself to allow internal functions and methods to have "complete type information in reflection."<ref>{{cite web |last1=Popov |first1=Nikita |title=Call for participation: Annotating internal function argument and return types |url=https://externals.io/message/106522 |website=Externals |access-date=19 November 2020}}</ref>
* Inheritance with private methods<ref name="Brent" />
* Abstract methods in traits improvements<ref name="Brent" />