rfc:nested_classes

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rfc:nested_classes [2013/10/01 23:24] – [Syntax Example] krakjoerfc:nested_classes [2017/09/22 13:28] (current) – external edit 127.0.0.1
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   * Date: 2013-09-29   * Date: 2013-09-29
   * Author: Joe Watkins, krakjoe@php.net   * Author: Joe Watkins, krakjoe@php.net
-  * Status: Under Discussion+  * Status: Withdrawn
   * First Published at: http://wiki.php.net/rfc/nested_classes   * First Published at: http://wiki.php.net/rfc/nested_classes
  
Line 41: Line 41:
   * public - the class is accessible everywhere   * public - the class is accessible everywhere
   * private - the class may be accessed by any class declared in the //outer// class   * private - the class may be accessed by any class declared in the //outer// class
-  * protected - the class may be accessed by any class up to and including the //outermost// class+  * protected - the class may be access by any class in the same virtual namespace
  
 ===== Private Classes ===== ===== Private Classes =====
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 In the example ''\foo'' is the public facing API, ''\foo\bar'' contains supporting logic never to be exposed outside of ''\foo'', any class declared in the virtual namespace ''\foo'' will be able to access the ''\foo\bar'' class. In the example ''\foo'' is the public facing API, ''\foo\bar'' contains supporting logic never to be exposed outside of ''\foo'', any class declared in the virtual namespace ''\foo'' will be able to access the ''\foo\bar'' class.
  
 +Attempting:
  
 +<code php>
 +var_dump(new \foo\bar());
 +</code>
 +
 +will result in
 +
 +<code>
 +Fatal error: Cannot access private class foo\bar from an unknown scope in %s on line %d
 +</code>
 +
 +Private classes are very private, the following example demonstrates this:
 +
 +<code php>
 +<?php
 +/*
 +* foo
 +* @package foo
 +*/
 +class foo 
 +{
 +    /*
 +    * foo\bar supporting class for foo
 +    * @subpackage foo\bar
 +    * @private
 +    */
 +    private class bar
 +    {
 +        
 +        /*
 +        * \foo\bar\baz supporting class for foo\bar
 +        * @subpackage foo\bar\baz
 +        * @private
 +        */
 +        private class baz 
 +        {
 +            
 +            public function __construct() {
 +                
 +            }    
 +        }
 +        
 +        public function __construct() {
 +            $this->baz = new foo\bar\baz();
 +        }
 +    }
 +    
 +    /* PUBLIC API METHODS HERE */
 +    
 +    public function __construct() 
 +    {
 +        $this->bar = new \foo\bar();
 +        $this->baz = new \foo\bar\baz(); /* line 39 */
 +    }
 +}
 +
 +new \foo();
 +?>
 +</code>
 +
 +Output:
 +
 +<code>
 +Fatal error: Cannot access private class foo\bar\baz from foo in %s on line 39
 +</code>
 +
 +===== Protecting bits of your Privates =====
 +
 +The following example shows how protected and private classes can be used in conjunction to provide versatile encapsulation:
 +
 +<code php>
 +<?php
 +/*
 +* foo
 +* @package foo
 +*/
 +class foo
 +{
 +    /*
 +    * foo\bar supporting class for foo
 +    * @subpackage foo\bar
 +    * @private
 +    */
 +    private class bar
 +    {
 + 
 +        /*
 +        * \foo\bar\baz supporting class for foo\bar
 +        * @subpackage foo\bar\baz
 +        * @protected
 +        */
 +        protected class baz
 +        {
 + 
 +            public function __construct() {
 + 
 +            }
 +        }
 + 
 +        public function __construct() {
 +            $this->baz = new foo\bar\baz();
 +        }
 +    }
 + 
 +    /* PUBLIC API METHODS HERE */
 + 
 +    public function __construct()
 +    {
 +        $this->bar = new \foo\bar();
 +        $this->baz = new \foo\bar\baz();
 +    }
 +}
 +
 +var_dump(new \foo());
 +</code>
 +
 +Output:
 +
 +<code>
 +object(foo)#1 (2) {
 +  ["bar"]=>
 +  object(foo\bar)#2 (1) {
 +    ["baz"]=>
 +    object(foo\bar\baz)#3 (0) {
 +    }
 +  }
 +  ["baz"]=>
 +  object(foo\bar\baz)#4 (0) {
 +  }
 +}
 +</code>
 +
 +The protected class ''\foo\bar\baz'' can now be used in ''\foo'', for example:
 +
 +<code php>
 +<?php
 +/*
 +* foo
 +* @package foo
 +*/
 +class foo
 +{
 +    /*
 +    * foo\bar supporting class for foo
 +    * @subpackage foo\bar
 +    * @private
 +    */
 +    private class bar
 +    {
 + 
 +        /*
 +        * \foo\bar\baz supporting class for foo\bar
 +        * @subpackage foo\bar\baz
 +        * @protected
 +        */
 +        protected class baz
 +        {
 + 
 +            public function __construct() {
 + 
 +            }
 +        }
 + 
 +        public function __construct() {
 +            $this->baz = new foo\bar\baz();
 +        }
 +    }
 +    
 +    /*
 +    * \foo\qux supporting class for foo
 +    */
 +    private class qux extends foo\bar\baz
 +    {
 +        public function __construct() {
 +            
 +        }
 +    }
 + 
 +    /* PUBLIC API METHODS HERE */
 + 
 +    public function __construct()
 +    {
 +        $this->bar = new \foo\bar();
 +        $this->baz = new \foo\bar\baz();
 +        $this->qux = new \foo\qux();
 +    }
 +}
 + 
 +var_dump(new \foo());
 +</code>
 +
 +Output:
 +
 +<code>
 +object(foo)#1 (3) {
 +  ["bar"]=>
 +  object(foo\bar)#2 (1) {
 +    ["baz"]=>
 +    object(foo\bar\baz)#3 (0) {
 +    }
 +  }
 +  ["baz"]=>
 +  object(foo\bar\baz)#4 (0) {
 +  }
 +  ["qux"]=>
 +  object(foo\qux)#5 (0) {
 +  }
 +}
 +</code>
 ===== Backward Incompatible Changes ===== ===== Backward Incompatible Changes =====
  
rfc/nested_classes.1380669871.txt.gz · Last modified: 2017/09/22 13:28 (external edit)

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