rfc:foreach_unwrap_ref

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
rfc:foreach_unwrap_ref [2021/08/13 13:11] – nikicrfc:foreach_unwrap_ref [2021/11/14 17:10] (current) – nikic
Line 2: Line 2:
   * Date: 2021-08-13   * Date: 2021-08-13
   * Author: Nikita Popov <nikic@php.net>   * Author: Nikita Popov <nikic@php.net>
-  * Status: Under Discussion+  * Status: Withdrawn
   * Target Version: PHP 8.2   * Target Version: PHP 8.2
   * Implementation: https://github.com/php/php-src/pull/7364   * Implementation: https://github.com/php/php-src/pull/7364
Line 56: Line 56:
 ===== Proposal ===== ===== Proposal =====
  
-This RFC proposes to change the semantics of foreach by reference to unwrap the reference after the loop. This means that ''$value'' will still have the value of the last (visited) element, but will no longer be a reference to it.+This RFC proposes to change the semantics of foreach by reference to unwrap the reference after the loop. This means that ''$value'' will still have the value of the last (visited) element, but will no longer be a reference to it. This also applies if the loop is left using ''break'', ''continue'' or ''goto''.
  
 While PHP does not have a dedicated language construct for reference unwrapping, the operation is logically equivalent to: While PHP does not have a dedicated language construct for reference unwrapping, the operation is logically equivalent to:
Line 98: Line 98:
  
 Use of complex variables as foreach targets is very unusual, so it is rather unlikely that someone will encounter issues with the reused loop variables in this context. Always performing the unwrap would certainly be possible, but the cure seems worse than disease in this instance. Use of complex variables as foreach targets is very unusual, so it is rather unlikely that someone will encounter issues with the reused loop variables in this context. Always performing the unwrap would certainly be possible, but the cure seems worse than disease in this instance.
 +
 +When foreach is used in conjunction with destructuring, unwrapping will be performed on simple destructuring targets:
 +
 +<PHP>
 +foreach ($array as [&$var, &$complex->var]) {}
 +</PHP>
 +
 +In this example, ''$var'' will be unwrapped because it is a simple variable, while ''$complex->var'' is not affected. As with the non-destructuring case, use of complex variables in this context is unusual and may have side-effects.
  
 ===== Backward Incompatible Changes ===== ===== Backward Incompatible Changes =====
rfc/foreach_unwrap_ref.1628860274.txt.gz · Last modified: 2021/08/13 13:11 by nikic

Page Tools