rfc:list_default_value

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rfc:list_default_value [2015/11/09 13:03] – reezerfc:list_default_value [2015/11/09 13:53] – reeze
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-====== PHP RFC:  Default Value in List Syntax ======+====== PHP RFC:  Default Value in List Assignment Syntax ======
   * Version: 0.1   * Version: 0.1
   * Date: 2015-11-08   * Date: 2015-11-08
   * Author: Reeze Xia, reeze@php.net   * Author: Reeze Xia, reeze@php.net
-  * Status: Draft+  * Status: Under Discussion
   * First Published at: http://wiki.php.net/rfc/list_default_value   * First Published at: http://wiki.php.net/rfc/list_default_value
  
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 <code php> <code php>
 +// basic syntax
 list($a, $b='default') = [1];      // a = 1, b = 'default' list($a, $b='default') = [1];      // a = 1, b = 'default'
 list($a, $b='default') = [1, 2];  // a = 1, b = 2 list($a, $b='default') = [1, 2];  // a = 1, b = 2
 +
 +//  comparation
 +list($a, list($b=1, $c=2) = $arr;
 +// opposite we need to
 +if (!isset($arr[1][0])) {
 +    $arr[1][0] = 1;
 +}
 +if (!isset($arr[1][1])) {
 +    $arr[1][0] = 2;
 +}
 +
 +$list($a, list($b, $c)) = $arr;
 +
 +
 +// other examples
 +function say_hello()
 +{
 +    return "Hello";
 +}
 +$name = 'PHP';
 +list($a=say_hello(), $b=$name."7.0") = []; // a = 'Hello', b = 'PHP7.0'
  
 list($a, list($b=1, $c=2)) = [1]; // a = 1, b = 1, c = 2 list($a, list($b=1, $c=2)) = [1]; // a = 1, b = 1, c = 2
 +
 </code> </code>
  
-The previous assignment could be considered as a shortcut for:+The assignment could be considered as a shortcut for:
  
 <code php> <code php>
 +
 +list($a, $b='deafult') = $arr;
 +
 +// equals
 +
 $a = $arr[0]; $a = $arr[0];
 $b = isset($arr[1]) ? $arr[1] : 'default'; $b = isset($arr[1]) ? $arr[1] : 'default';
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 More case could be found from PR's tests:  [[https://github.com/php/php-src/pull/1623/files]] More case could be found from PR's tests:  [[https://github.com/php/php-src/pull/1623/files]]
  
-This feature could be find in [[https://clojurebridge.github.io/community-docs/docs/clojure/destructuring/|Clojure]] and [[https://hacks.mozilla.org/2015/05/es6-in-depth-destructuring/|Javascript]].  +This feature could also be found in [[https://clojurebridge.github.io/community-docs/docs/clojure/destructuring/|Clojure]] and [[https://hacks.mozilla.org/2015/05/es6-in-depth-destructuring/|Javascript]] for destructing. 
  
 ===== Backward Incompatible Changes ===== ===== Backward Incompatible Changes =====
-What breaks, and what is the justification for it?+ 
 +No BC break.
  
 ===== Proposed PHP Version(s) ===== ===== Proposed PHP Version(s) =====
-List the proposed PHP versions that the feature will be included in.  Use relative versions such as "next PHP 5.x" or "next PHP 5.x.y".+PHP 7.1
  
 ===== RFC Impact ===== ===== RFC Impact =====
-==== To SAPIs ==== 
-Describe the impact to CLI, Development web server, embedded PHP etc. 
- 
-==== To Existing Extensions ==== 
-Will existing extensions be affected? 
  
 ==== To Opcache ==== ==== To Opcache ====
-It is necessary to develop RFC's with opcache in mind, since opcache is a core extension distributed with PHP. 
  
-Please explain how you have verified your RFC's compatibility with opcache. +I am working on opcache compatibility.
- +
-==== New Constants ==== +
-Describe any new constants so they can be accurately and comprehensively explained in the PHP documentation. +
- +
-==== php.ini Defaults ==== +
-If there are any php.ini settings then list: +
-  * hardcoded default values +
-  * php.ini-development values +
-  * php.ini-production values+
  
 ===== Open Issues ===== ===== Open Issues =====
-Make sure there are no open issues when the vote starts! +None for now
- +
-===== Unaffected PHP Functionality ===== +
-List existing areas/features of PHP that will not be changed by the RFC. +
- +
-This helps avoid any ambiguity, shows that you have thought deeply about the RFC's impact, and helps reduces mail list noise.+
  
 ===== Future Scope ===== ===== Future Scope =====
-This sections details areas where the feature might be improved in future, but that are not currently proposed in this RFC. 
  
 ===== Proposed Voting Choices ===== ===== Proposed Voting Choices =====
-Include these so readers know where you are heading and can discuss the proposed voting options. 
  
-State whether this project requires a 2/3 or 50%+1 majority (see [[voting]])+* Whether accept the RFC for PHP 7.1 
 + 
 +This project requires a 2/3 majority (see [[voting]])
  
 ===== Patches and Tests ===== ===== Patches and Tests =====
-Links to any external patches and tests go here. 
  
-If there is no patch, make it clear who will create a patch, or whether a volunteer to help with implementation is needed.+* Patch: [[https://github.com/php/php-src/pull/1623]]
  
-Make it clear if the patch is intended to be the final patch, or is just a prototype.+I am working on opcache compatibility
  
 ===== Implementation ===== ===== Implementation =====
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 ===== Rejected Features ===== ===== Rejected Features =====
-Keep this updated with features that were discussed on the mail lists.+ 
 +===== Changelog ===== 
 + 
 +  * v0.1 - Initial version
rfc/list_default_value.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

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