rfc:closures:removal-of-this

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rfc:closures:removal-of-this [2009/01/26 12:27]
cseiler created
rfc:closures:removal-of-this [2017/09/22 13:28]
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-====== Removal of $this in closures ====== 
  
-(NOTE THAT THIS IS NOT COMMITTED YET. THIS PAGE IS STILL WORK IN PROGRESS) 
- 
-This document describes the changes that were done in order to remove $this support from closures for PHP 5.3 beta1. This has become necessary in order to make sure that when a consensus is found on how to add $this to closures, it will be able to integrate that without BC issues. 
- 
-===== Userland perspective ===== 
- 
-In the userland perspective, $this may not be used in closures. Also, using the static keyword in front of function is not allowed anymore. Examples: 
- 
-<code php> 
-$closure = function () { }; // still works 
-$closure = static function () { }; // DOES NOT WORK 
-class Foo { 
-  public $pubMember; 
-  private $privMembeR; 
-  function bar { 
-    $closure = function () { 
-      return $this; // DOES NOT WORK 
-    }; 
-    $closure = static function () { // DOES NOT WORK 
-    }; 
-    $closure = function () { echo "Hello World!\n"; }; // still works 
-    $closure = function () use ($this) { ... }; // DOES NOT WORK 
-    $self = $this; 
-    $closure = function () use ($self) { // still works 
-       echo $self->pubMember; // still works 
-       echo $self->privMember; // DOES NOT WORK 
-    }; 
-  } 
-} 
-</code> 
- 
-Yes, these are quite some restrictions on closures, however, this is the only possibility to ensure that support for $this can be added in any fashion that may later be required. 
- 
-===== Internals perspective ===== 
- 
-   - zend_closure structure: this_ptr member is gone. 
-   - removed zend_get_closure() prototype in zend_closures.h (was not implemented anyway anymore since it's now done via a handler) 
-   - removd scope and this_ptr parameters from zend_create_closure() 
-   - removed zend_get_closure_this_ptr 
- 
-==== Important note on get_closure handler ==== 
- 
-However, the get_closure handler prototype was **NOT** changed (only the implementation for closures, which always set the scope and object ptr to NULL) and still allows the handler implementation to set a scope and this_ptr because the handler is also responsible for __invoke on normal objects! 
- 
-===== Reflection ===== 
- 
-TBD. 
rfc/closures/removal-of-this.txt · Last modified: 2017/09/22 13:28 (external edit)