rfc:closure_apply

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rfc:closure_apply [2014/07/30 00:30] – v0.2, changed name from ::apply to ::call ajfrfc:closure_apply [2014/08/17 19:31] – Opened vote ajf
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 ====== PHP RFC: Closure::call ====== ====== PHP RFC: Closure::call ======
-  * Version: 0.2 +  * Version: 0.2.1 
-  * Date: 2014-07-29+  * Date: 2014-07-29, put to internals 2014-08-03, latest 2014-08-17
   * Author: Andrea Faulds, ajf@ajf.me   * Author: Andrea Faulds, ajf@ajf.me
-  * Status: Draft+  * Status: In Voting
   * First Published at: http://wiki.php.net/rfc/closure_apply   * First Published at: http://wiki.php.net/rfc/closure_apply
  
 ===== Introduction ===== ===== Introduction =====
  
-PHP has had Closures since 5.3, and since 5.4 has had ''Closure::bind'' (static method) and ''Closure::bindTo'' (method) to allow creating new closures that have ''$this'' bound to a specific method. However, it has not been possible to bind at call-time without creating a new closure, making binding to different objects and calling for multiple objects cumbersome and inefficient (at least two statements are needed, and a new closure must be created and immediately disposed of for each).+PHP has had Closures since 5.3, and since 5.4 has had ''Closure::bind'' (static method) and ''Closure::bindTo'' (method) to allow creating new closures that have ''$this'' bound to a specific method. However, it has not been possible to bind at call-time, and you must instead create a temporary new closure, making calling bound to multiple objects cumbersome and inefficient (at least two statements are needed, and a new closure must be created and immediately disposed of for each).
  
 ===== Proposal ===== ===== Proposal =====
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 </code> </code>
  
-My function referencing as closures proposal similarly relaxes the requirement for a scoped closure to be bound or static out of necessity, and ''->call'' would be highly useful to that proposal, so this RFC can be considered a prerequisite to it.+My [[rfc:function_referencing|Function Referencing as Closures]] proposal similarly relaxes the requirement for a scoped closure to be bound or static out of necessity, and ''->call'' would be highly useful to that proposal, so this RFC can be considered a prerequisite to it. 
 + 
 +''call'' would be useful in many cases where ''bindTo'' is used (e.g. [[https://github.com/search?l=php&p=34&q=bindTo&ref=cmdform&type=Code|search of GitHub for bindTo]]). A search on GitHub reveals [[https://github.com/search?q=bindTo+call_user_func&type=Code&ref=searchresults|many using bindTo and immediately calling with call_user_func]], which would now not be necessary as they could just use ''call''. 
 + 
 +===== Performance ===== 
 + 
 +While not the sole benefit of this RFC, it can provide a performance improvement in some applications. 
 + 
 +We use two test scripts, ''a.php'' using bindTo and ''b.php'' using call. 
 + 
 +<file php a.php> 
 +$a = function () { 
 +    return $this->x; 
 +}; 
 +class FooBar { 
 +    private $x = 3; 
 +} 
 +$foobar = new FooBar; 
 +for ($i = 0; $i < 100000; $i++) { 
 +    $x = $a->bindTo($foobar, "FooBar"); 
 +    $x(); 
 +} 
 +</file> 
 + 
 +<file php b.php> 
 +$a = function () { 
 +    return $this->x; 
 +}; 
 +$a = $a->bindTo(NULL, "FooBar", true); 
 +class FooBar { 
 +    private $x = 3; 
 +} 
 +$foobar = new FooBar; 
 +for ($i = 0; $i < 100000; $i++) { 
 +    $a->call($foobar); 
 +} 
 +</file> 
 + 
 +When run for 100000 iterations, ''b.php'' shows a 2x improvement over ''a.php'': 
 + 
 +<code> 
 +andreas-air:php-src ajf$ time sapi/cli/php a.php 
 +  
 +real 0m0.259s 
 +user 0m0.208s 
 +sys 0m0.012s 
 +  
 +andreas-air:php-src ajf$ time sapi/cli/php b.php 
 +  
 +real 0m0.100s 
 +user 0m0.094s 
 +sys 0m0.005s 
 +</code> 
 +  
 +If we up the iterations by 10x, the result is the same: 
 + 
 +<code> 
 +andreas-air:php-src ajf$ time sapi/cli/php a.php 
 +  
 +real 0m1.966s 
 +user 0m1.959s 
 +sys 0m0.005s 
 +  
 +andreas-air:php-src ajf$ time sapi/cli/php b.php 
 +  
 +real 0m0.962s 
 +user 0m0.897s 
 +sys 0m0.015s 
 +</code>
  
 ===== Backward Incompatible Changes and RFC Impact ===== ===== Backward Incompatible Changes and RFC Impact =====
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 Partial application (where a new closure is returned that pre-fills the first X arguments) is a possibly worthwhile (though more difficult to implement) addition. Partial application (where a new closure is returned that pre-fills the first X arguments) is a possibly worthwhile (though more difficult to implement) addition.
  
-===== Proposed Voting Choices =====+===== Vote =====
  
 This is not a language change, so a straight 50%+1 Yes/No vote can be held. This is not a language change, so a straight 50%+1 Yes/No vote can be held.
 +
 +Voting started 2014-08-17 and ends 2014-08-24.
 +
 +<doodle title="Merge Closure::call() patch into master?" auth="ajf" voteType="single" closed="false">
 +   * Yes
 +   * No
 +</doodle>
  
 ===== Patches and Tests ===== ===== Patches and Tests =====
  
 A branch which implements this (with a test) based on the current master can be found here: https://github.com/TazeTSchnitzel/php-src/tree/Closure_apply A branch which implements this (with a test) based on the current master can be found here: https://github.com/TazeTSchnitzel/php-src/tree/Closure_apply
 +
 +There is a pull request for review purposes here: https://github.com/php/php-src/pull/775
  
 ===== References ===== ===== References =====
  
-  * As aforementioned, my [[rfc:function_referencing|Function Referencing as Closures]] RFC has this RFC as a prerequisite+  * As previously mentioned, my [[rfc:function_referencing|Function Referencing as Closures]] RFC has this RFC as a prerequisite
  
 ===== Changelog ===== ===== Changelog =====
  
 +  * v0.2.1 - Added performance section
   * v0.2 - ''Closure::apply'' renamed to ''Closure::call'' for consistency with JavaScript (former takes an array in JS à la ''call_user_func_array'', latter bare parameters)   * v0.2 - ''Closure::apply'' renamed to ''Closure::call'' for consistency with JavaScript (former takes an array in JS à la ''call_user_func_array'', latter bare parameters)
   * v0.1 - Initial version   * v0.1 - Initial version
rfc/closure_apply.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

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