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--- rfc:traits [2008/03/06 21:15] – created gron
+++ rfc:traits [2017/09/22 13:28] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-====== Request for Comments: Traits for PHP ======
+====== Request for Comments: Traits for PHP (Superseded by Horizontal Reuse for PHP) ======
   * Version: 1.5
+  * Date: 2008-03-06
+  * Author: Stefan Marr <php.at.stefan-marr.de>
+  * Status: **Superseded by [[rfc:HorizontalReuse|Horizontal Reuse for PHP]]**
+  * Patch: http://www.stefan-marr.de/archives/20-New-Traits-Patch-Ready-for-Testing.html
   * First Published at: http://www.stefan-marr.de/artikel/rfc-traits-for-php.html
   * reST TXT: http://www.stefan-marr.de/rfc-traits-for-php.txt
-  * Author: Stefan Marr <php.at.stefan-marr.de>
 This RFC will discuss at first the motivation for Traits describing the rationals
@@ Line 11: / Line 15: @@
 additional resources about Traits are given.
+**This RFC is outdated and replaced by [[rfc:HorizontalReuse|RFC: Horizontal Reuse for PHP]].**
 ===== Introduction =====
@@ Line 104: / Line 109: @@
 The next sections will discuss on more advanced techniques and describe how the
 current implementation of Traits for PHP works.
 ==== The Flattening Property ====
@@ Line 259: / Line 265: @@
  class Talker {
    use A, B {
-     B::smallTalk instead A::smallTalk,
+     B::smallTalk instead A;
-     A::bigTalk instead B::bigTalk
+     A::bigTalk instead B;
    }
  }
@@ Line 275: / Line 281: @@
  class Talker {
    use A, B {
-     B::smallTalk instead A::smallTalk,
+     B::smallTalk instead A;
-     A::bigTalk instead B::bigTalk,
+     A::bigTalk instead B;
-     A::bigTalk as talk
+     A::bigTalk as talk;
    }
  }
@@ Line 290: / Line 296: @@
 class will consist of following three methods:
-* ''bigTalk() { echo 'A'; }''
+  * ''bigTalk() { echo 'A'; }''
-* ''smallTalk() { echo 'b'; }''
+  * ''smallTalk() { echo 'b'; }''
-* ''talk() { echo 'B'; }''
+  * ''talk() { echo 'B'; }''
 Since the alias operation adds a new name to an existing method body, the
@@ Line 498: / Line 504: @@
 This section collects proposals for alternative Traits syntaxes.
+==== Scala Synthax and practical example ====
+This is inpired from [[http://www.scala-lang.org/node/117]].
+<code php>
+trait User_Comments
+{
+     function addComment($c)
+     {
+           $db = App::getDb();
+           $db->Execute("INSERT INTO user_comments (type, type_id, user_id, text)VALUES ($c->type, $c->type_id, $c->uid, $c->text)");
+     }
+     function getComments($filter)
+     {
+           return array();
+     }
+     function removeComment($id)
+     {
+           $db = App::getDb();
+           $db->Execute("DELETE FROM user_comments ... ");
+     }
+}
+class App_Email with User_Comments {}
+class App_Document with User_Comments  {
+     function removeComment($id)
+     {
+           $db = App::getDb();
+           $db->Execute("DELETE FROM user_comments ... ");
+           $db->Execute("UPDATE app_documents SET comments_count = ... ");
+     }
+}
+// PHP notice : 'User_Comments::removeComment() definition skipped in App_Document'
+$doc = new App_Document;
+echo is_a($doc, 'App_Document');     // true
+echo is_a($doc, 'User_Comments');    // false
+echo is_with($doc, 'User_Comments'); // true
+</code>
+We deal with conflicting class definitions by simply ignoring them.
+<code php>
+trait Conflict_Comments
+{
+     function removeComment($id)
+     {
+           return false;
+     }
+}
+class App_Document_Conflict with User_Comments, Conflict_Comments  {
+     function removeComment($id)
+     {
+           $db = App::getDb();
+           $db->Execute("DELETE FROM user_comments ... ");
+           $db->Execute("UPDATE app_documents SET comments_count = ... ");
+     }
+}
+// PHP notice : 'User_Comments::removeComment() definition skipped in App_Document_Conflict'
+// PHP notice : 'Conflict_Comments::removeComment() definition skipped in App_Document_Conflict'
+$doc = new App_Document_Conflict;
+echo is_a($doc, 'App_Document_Conflict');// true
+echo is_with($doc, 'User_Comments');     // true
+echo is_with($doc, 'Conflict_Comments'); // true
+</code>
 === Alternative Keywords for use ===
@@ Line 680: / Line 763: @@
 Last but not least, in this Phd thesis http://www.iam.unibe.ch/~scg/Archive/PhD/schaerli-phd.pdf
 two case studies have been publish illustrating the benefits Traits are providing.
 ===== Changelog =====
-gron 2008-03-05 14:15:45
+gron 2008-03-05 14:15:45\\
 - added new style of traits composition and replaced the notion of an explicit exclude operator in favor for a very explicit conflict resolution
-gron 2008-02-25 16:08:35
+gron 2008-02-25 16:08:35\\
 - fixed version number and some typos
-gron 2008-02-23 18:57:21
+gron 2008-02-23 18:57:21\\
-- added an example to the aliasing vs renaming part illustrating the effect on recursion
+- added an example to the aliasing vs renaming part illustrating the effect on recursion\\
 - added a syntax proposal which expresses the opposing character of aliasing(add) and excluding(remove) very well
-gron 2008-02-21 23:02:01
+gron 2008-02-21 23:02:01\\
-- added several new notation proposals
+- added several new notation proposals\\
 - added link to patch for PHP_5_3
-gron 2008-02-20 18:47:17
+gron 2008-02-20 18:47:17\\
-- introduced explicit description of abstract methods to be used as requirements specification for traits (useful to access state)
+- introduced explicit description of abstract methods to be used as requirements specification for traits (useful to access state)\\
-- moved part about interface propagation to the section of rejected features
+- moved part about interface propagation to the section of rejected features\\
-- added a section about common misconceptions i.e. aliasing is not renaming
+- added a section about common misconceptions i.e. aliasing is not renaming\\
 - added various syntax proposals

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