rfc:list_default_value

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rfc:list_default_value [2015/11/09 13:08] – 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) = $arr;
 +// or we need to check it ourself
 +if (!isset($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';
Line 67: Line 95:
  
 ===== RFC Impact ===== ===== RFC Impact =====
-==== To SAPIs ==== 
-No impact 
- 
-==== To Existing Extensions ==== 
-No impact 
  
 ==== To Opcache ==== ==== To Opcache ====
  
 I am working on opcache compatibility. I am working on opcache compatibility.
- 
-==== New Constants ==== 
-None 
- 
-==== php.ini Defaults ==== 
-None 
  
 ===== Open Issues ===== ===== Open Issues =====
 None for now None for now
- 
-===== Unaffected PHP Functionality ===== 
-No BC break 
  
 ===== Future Scope ===== ===== Future Scope =====
- 
  
 ===== Proposed Voting Choices ===== ===== Proposed Voting Choices =====
Line 117: Line 130:
 ===== Rejected Features ===== ===== Rejected Features =====
  
 +===== 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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