rfc:abstract_final_class

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rfc:abstract_final_class [2014/11/27 04:00]
guilhermeblanco fixed title
rfc:abstract_final_class [2017/09/22 13:28] (current)
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-====== PHP RFC: Abstract final classes ====== +====== PHP RFC: Static ​classes ====== 
-  * Version: 1.0+  * Version: 1.1
   * Date: 2014-11-26   * Date: 2014-11-26
   * Author: Guilherme Blanco, guilhermeblanco@php.net   * Author: Guilherme Blanco, guilhermeblanco@php.net
-  * Status: ​Under Discussion+  * Status: ​Declined
   * First Published at: http://​wiki.php.net/​rfc/​abstract_final_class   * First Published at: http://​wiki.php.net/​rfc/​abstract_final_class
  
 ===== Introduction ===== ===== Introduction =====
  
-Abstract final classes are helpful in the case you are wrapping common functions that are static, but the common class itself cannot be instantiated.+Please understand only one of the following proposals can be accepted, not both. 
 +They'​re explained together because the address the same issue. 
 + 
 +==== As Static classes ==== 
 + 
 + 
 +Static ​classes are helpful in the case you are wrapping common functions that are static, but the common class itself cannot be instantiated.
 Currently, PHP developers'​ only resource is to create a final class with a private constructor,​ leading to untestable and error prone code. Currently, PHP developers'​ only resource is to create a final class with a private constructor,​ leading to untestable and error prone code.
 +
 +When untestable/​error prone code is mentioned is that there'​s no signaling of broken definition by creating a regular class with private constructor and other members are not declared as static. Everything will just compile smoothly (file inclusion/​autoloading).
 +
 +By the acceptance of this patch, every method declaration would automatically be enforced to behave as static without any further keyword needed. This reduces the human error of methods being forgotten to be declared as static.
  
 For such, here is motivation: For such, here is motivation:
  
-  * As "abstract", it cannot be instantiated +  * As "static", it purely behaves at class level, not at instance level 
-  * As "​final",​ it cannot be extended (such as visibility ​increase, behavior change, etc) +  * Could also be used with combination of "​final", ​meaning ​it cannot be extended (such as more permissive ​visibility, behavior change, etc) 
-  * There'​s no way of adding variables to a namespace. This would address this issue too+  * There'​s no way of adding static variables to a namespace. This would address this issue too. 
 + 
 +==== As abstract final ==== 
 + 
 + 
 + 
 +Abstract final classes are helpful in the case you are wrapping common functions that are static, but the common class itself cannot be instantiated. Currently, PHP developers'​ only resource is to create a final class with a private constructor,​ leading to untestable and error prone code. 
 + 
 +For such, here is motivation:​ 
 + 
 +    As “abstract”,​ it cannot be instantiated 
 +    As “final”,​ it cannot be extended (such as visibility increase, behavior change, etc) 
 +    ​There'​s no way of adding variables to a namespace. This would address this issue too
  
 ===== Proposal ===== ===== Proposal =====
  
-Change language scanner to accept abstract final class constructor, and subsequently ​restricting to only static members.+Change language scanner to accept ​static class or abstract final construction, and subsequently ​enforcing the existence of only static members.
  
 ===== Proposed PHP Version(s) ===== ===== Proposed PHP Version(s) =====
Line 26: Line 48:
  
 ===== Example ===== ===== Example =====
 +
 +==== As static class ====
 +
 +  static class Environment
 +  {
 +      private static $rootDirectory = '/​var/​www/​project';​
 +      public static function getRootDirectory()
 +      {
 +          return self::​$rootDirectory;​
 +      }
 +  }
 +
 +  echo Environment::​getRootDirectory();​
 +
 +==== As abstract final ====
  
   abstract final class StringUtil   abstract final class StringUtil
Line 36: Line 73:
  
   echo StringUtil::​isNotNullOrSpace(''​)   echo StringUtil::​isNotNullOrSpace(''​)
-      ​? 'Empty string'​ +    ​? 'Empty string'​ 
-      : '​Non-empty string';​+    : '​Non-empty string';​
  
-===== Proposed Voting Choices ===== 
  
-Good question... 2/3? or 50% + 1?+===== Vote ===== 
 +<doodle title="​Static classes"​ auth="​guilhermeblanco"​ voteType="​single"​ closed="​true">​ 
 +   * Yes, as "​static class"​ 
 +   * Yes, as "​abstract final class"​ 
 +   * No 
 +</​doodle>​ 
 +\\ 
 +The vote starts on 12/12/2014 and ends on 12/19/2014. 2/3 majority required.
  
 ===== Implementation ===== ===== Implementation =====
  
-https://​github.com/​php/​php-src/​pull/​923+  * Most recent suggested implementation available at https://​github.com/​php/​php-src/​pull/​929 
 +  * Originally suggested as abstract class at https://​github.com/​php/​php-src/​pull/​923
rfc/abstract_final_class.1417060830.txt.gz · Last modified: 2017/09/22 13:28 (external edit)