From 7c77bc80b2079a18cd340c666dae2d6f760e97d2 Mon Sep 17 00:00:00 2001
From: John Wellbelove <github@wellbelove.co.uk>
Date: Sat, 30 Mar 2019 10:40:19 +0000
Subject: [PATCH] Added C++11 variadic template version of etl::observer

---
 include/etl/observer.h    | 35 +++++++++++++++++++++++++++++++++--
 include/etl/version.h     |  2 +-
 support/Release notes.txt |  4 ++++
 3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/include/etl/observer.h b/include/etl/observer.h
index 06d07dfc..dcc1edb3 100644
--- a/include/etl/observer.h
+++ b/include/etl/observer.h
@@ -186,17 +186,46 @@ namespace etl
     }
 
   protected:
-      
+
     ~observable()
     {
     }
-	  
+
   private:
 
     /// The list of observers.
     Observer_List observer_list;
   };
 
+#if ETL_CPP11_SUPPORTED && !defined(ETL_OBSERVER_FORCE_CPP03)
+
+  //*****************************************************************
+  /// The observer class for N types.
+  ///\ingroup observer
+  //*****************************************************************
+  template <typename T1, typename... Types>
+  class observer : public observer<T1>, public observer<Types...>
+  {
+  public:
+
+    using observer<T1>::notification;
+    using observer<Types...>::notification;
+  };
+
+  //*****************************************************************
+  /// The specialised observer class for 1 type.
+  ///\ingroup observer
+  //*****************************************************************
+  template <typename T1>
+  class observer<T1>
+  {
+  public:
+
+    virtual void notification(T1) = 0;
+  };
+
+#else
+
   //*********************************************************************
   /// The observer interface for eight notification types.
   ///\ingroup observer
@@ -355,6 +384,8 @@ namespace etl
     virtual ~observer() {}
     virtual void notification(T1) = 0;
   };
+
+#endif
 }
 
 #undef ETL_FILE
diff --git a/include/etl/version.h b/include/etl/version.h
index 765ded77..85d56f97 100644
--- a/include/etl/version.h
+++ b/include/etl/version.h
@@ -38,7 +38,7 @@ SOFTWARE.
 ///\ingroup utilities
 
 #define ETL_VERSION_MAJOR 14
-#define ETL_VERSION_MINOR 16
+#define ETL_VERSION_MINOR 17
 #define ETL_VERSION_PATCH  0
 
 #define ETL_VERSION       ETL_STRINGIFY(ETL_VERSION_MAJOR) ETL_STRINGIFY(ETL_VERSION_MINOR) ETL_STRINGIFY(ETL_VERSION_PATCH)
diff --git a/support/Release notes.txt b/support/Release notes.txt
index 594e30a8..1ef4d2dc 100644
--- a/support/Release notes.txt	
+++ b/support/Release notes.txt	
@@ -1,3 +1,7 @@
+===============================================================================
+14.17.0
+Added C++11 variadic templates for etl::observer.
+
 ===============================================================================
 14.16.0
 Added C++11 variadic templates for etl::visitable and etl::visitor.