rfc:class_const_visibility

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rfc:class_const_visibility [2015/03/04 04:11] – reezerfc:class_const_visibility [2015/12/03 13:56] – Update status ajf
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 ====== PHP RFC: Support Class Constant Visibility ====== ====== PHP RFC: Support Class Constant Visibility ======
-  * Version: 0.1 +  * Version: 0.2 
-  * Date: 2015-03-03 +  * Date: 2015-09-13 
-  * Author: Reeze Xia, reeze@php.net +  * Author: Sean DuBois <sean@siobud.com>, Reeze Xia <reeze@php.net> 
-  * Status: Draft+  * Status: Accepted
   * First Published at: http://wiki.php.net/rfc/class_const_visibility   * First Published at: http://wiki.php.net/rfc/class_const_visibility
  
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 ===== Introduction ===== ===== Introduction =====
  
-Currently class method and member have visibility control, but class contants are not. +Classes in PHP allow modifiers on properties and methods, but not constants. 
-They are always be public.+It is an easily fixed inconsistency, and a feature that many want and most surprised 
 +that it doesn't already exist.  [[http://stackoverflow.com/questions/5339456/php-class-constant-visibility|Stack Overflow Thread]]
  
-In real application, one might want to limit class constant's +In a thread on php-internals a couple real world examples were offered. 
-visibility for better encapsulation. +    * Defining bitmasks/magic numbers, but not exposing them globally. Before constants would be exposed allowing callers to depend on them. 
- +    * Help make it more clear what is important, exposing harmless constants clutters documentation  needlessly. 
-This RFC intend to introduce class constants' visibility.+
  
 ===== Proposal ===== ===== Proposal =====
  
-This RFC propose PHP support class constant visibilty. The syntax is straightfoward as +This RFC propose PHP support class constant visibility that mirror the behavior of method 
-other member visibility modifiers.+and property visibility. 
  
 Class constant may be define as public, private or protected. class constants declared Class constant may be define as public, private or protected. class constants declared
-without any explict visibility keyword are defined as public.+without any explicit visibility keyword are defined as public. 
  
 Proposed syntax: Proposed syntax:
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 class Token { class Token {
- // Deault: declear public class constants as before + // Constants default to public 
- const T_ISSET = 0; + const PUBLIC_CONST = 0;
- const T_ECHO = 1; +
-}+
  
-echo Token::T_ISSET; // accessiable +        // Constants then also can have a defined visibility 
- +        private const PRIVATE_CONST = 0; 
- +        protected const PROTECTED_CONST = 0; 
-// no special limit, the same as normal class +        public const PUBLIC_CONST_TWO = 0; 
-abstract class AbstractClass { +         
- // constant definitions.+        //Constants can only have one visibility declaration list 
 +        private const FOO = 1, BAR = 2;
 } }
  
-trait Trait1 { 
- // traits are not allowed to define constant as before 
- public const TCONS = 10; // error 
-} 
  
 +//Interfaces only support public consts, and a compile time error will be thrown for anything else. Mirroring the behavior of methods.
 interface ICache { interface ICache {
- private const CANNOT_BE_PRIVATE = 1;     // error interface can only have pulic class const +        public const PUBLIC = 0; 
- protected const CANNOT_BE_PROTECTED = 2; +        const IMPLICIT_PUBLIC = 1;
- +
- public function get($k, $v); +
- public function set($k);+
 } }
  
-class CacheStorage extends ICache { +</code>
- protected const CACHE_KEY_PREFIX = "";+
  
- public const STORAGE_NAME = "Unknow"; 
-} 
  
-class RedisCacheStorage extends CacheStorage { +===== Backward Incompatible Changes =====
- private const DEFAULT_HOST = "127.0.0.1"; +
- private const DEFAULT_PORT = "8129"; +
- protected const CACHE_KEY_PREFIX = "my_redis_cache_prefix_";+
  
- public const STORAGE_NAME = "redis";+==== Reflection Ext ==== 
 +The reflection extension has been updated to expose constants like [[ReflectionProperty|http://php.net/manual/en/class.reflectionproperty.php]]. 
  
- private $con; +Instead of getConstant/getConstants returning values there is now a dedicated ReflectionClassConstant class.
- public function __construct() { +
- echo parent:: CACHE_KEY_PREFIX; // access parent;+
  
- $this->con = redis_fake_always_success_connect(self::DEFAULT_HOST, self::DEFAULT_PORT); +<code php> 
- } +<?php
- +
- public function set($k, $v) { +
- return redis_fake_set($this, self::CACHE_KEY_PREFIX . $k, $v); +
- }+
  
- public function get($k) { +class testClass  { 
- return redis_fake_set($this, self::CACHE_KEY_PREFIX . $k, $v); +  const TEST_CONST = 'test';
- }+
 } }
  
-echo RedisCacheStorage::DEFAULT_HOST; // cloudn't access +$obj = new ReflectionClass( "testClass" ); 
-echo RedisCacheStorage::CACHE_KEY_PREFIX; // cloudn't access +$const = $obj->getConstant( "TEST_CONST" ); 
-echo RedisCacheStorage::STORAGE_NAME; // Yes we can +$const->__toString(); 
 +$const->getName(); 
 +$const->getValue(); 
 +$const->isPublic(); 
 +$const->isPrivate(); 
 +$const->isProtected(); 
 +$const->getModifiers(); 
 +$const->getDeclaringClass();
 </code> </code>
- 
-===== Backward Incompatible Changes ===== 
- 
-No BC break. 
  
 ===== Proposed PHP Version(s) ===== ===== Proposed PHP Version(s) =====
  
-PHP7+This RFC targets PHP 7.1
  
 ===== RFC Impact ===== ===== RFC Impact =====
 +
 ==== To SAPIs ==== ==== To SAPIs ====
-No+ 
 +None.
  
 ==== To Existing Extensions ==== ==== To Existing Extensions ====
  
-Maybe? Need to check.+None, all the class constant APIs will be the same. 
 +There will be new _ex APIs that allow callers to explicitly pass flags. 
 + 
 +If a extension accesses non-public structures (the now non-existent class_constants HashTable) there will be breakage
  
 ==== To Opcache ==== ==== To Opcache ====
  
-Need update. Will try to do it later.+Need update.
  
-==== New Constants ====+===== Vote =====
  
-None+Simple Yes/No option. This requires a 2/3  majority.
  
-==== php.ini Defaults ====+This vote will close on 06:00 UTC on Tuesday 2015-10-27
  
-None +<doodle title="Class Constant Visibility" auth="sdubois" voteType="single" closed="true"> 
- +   * Yes 
-===== Open Issues ===== +   * No 
- +</doodle>
- +
-===== Unaffected PHP Functionality ===== +
- +
- +
-===== Future Scope ===== +
- +
-Support final modifier? Need another RFC upon this. +
- +
- +
-===== Proposed Voting Choices ===== +
- +
-Simple Yes/No option. This requires a 2/3  majority.+
  
 ===== Patches and Tests ===== ===== Patches and Tests =====
  
-Work In Progress. TODO+A pull request has been made. It is feature complete but needs review, more tests, and help with opcache changes : https://github.com/php/php-src/pull/1494
  
-Make it clear if the patch is intended to be the final patch, or is just a prototype. 
- 
-===== Implementation ===== 
- 
-TBD 
  
 ===== References ===== ===== References =====
-- http://php.net/manual/en/language.oop5.constants.php +  * http://php.net/manual/en/language.oop5.constants.php 
-- http://php.net/manual/en/language.oop5.visibility.php +  * http://php.net/manual/en/language.oop5.visibility.php
- +
-===== Rejected Features ===== +
- +
-None+
  
 ===== Changelog ===== ===== Changelog =====
  
-- V0.1 Initial version+  * V0.1 Initial version 
 +  * V0.2 Adopted by Sean DuBois <sean@siobud.com>
rfc/class_const_visibility.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

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