From ad0e3c4f8d9d94c6dc79ff12256854b296c0baab Mon Sep 17 00:00:00 2001
From: jwellbelove <john.wellbelove@raymarine.com>
Date: Wed, 16 Nov 2016 14:04:19 +0000
Subject: [PATCH] Added +-*/ operators. Added bool conversion operator. Added !
 operator. get() returns const reference.

---
 src/type_def.h | 42 +++++++++++++++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 3 deletions(-)

diff --git a/src/type_def.h b/src/type_def.h
index 66d6156e..707a0732 100644
--- a/src/type_def.h
+++ b/src/type_def.h
@@ -40,11 +40,11 @@ namespace etl
     /// Usage:
     ///\code
     /// // Short form.
-    /// ETL_TYPEDEF(int, mytype);
+    /// ETL_TYPEDEF(int, mytype_t);
     /// 
     /// // Long form.
     /// class mytype_t_tag;
-    /// typedef etl::type_def<mytype_t_tag, int> mytype_t_tag;
+    /// typedef etl::type_def<mytype_t_tag, int> mytype_t;
     ///\endcode
     //*************************************************************************
     template <typename TIdType, typename TValue>
@@ -79,6 +79,18 @@ namespace etl
             return value;
         }
 
+        //*********************************************************************
+        explicit operator bool() const
+        {
+            return static_cast<bool>(value);
+        }
+
+        //*********************************************************************
+        bool operator !() const
+        {
+            return !bool(value);
+        }
+
         //*********************************************************************
         type_def& operator ++()
         {
@@ -243,11 +255,35 @@ namespace etl
         }
 
         //*********************************************************************
-        TValue get() const
+        const TValue& get() const
         {
             return value;
         }
 
+        //*********************************************************************
+        friend type_def operator +(const type_def& lhs, const type_def& rhs)
+        {
+            return type_def(lhs.value + rhs.value);
+        }
+
+        //*********************************************************************
+        friend type_def operator -(const type_def& lhs, const type_def& rhs)
+        {
+            return type_def(lhs.value - rhs.value);
+        }
+
+        //*********************************************************************
+        friend type_def operator *(const type_def& lhs, const type_def& rhs)
+        {
+            return type_def(lhs.value * rhs.value);
+        }
+
+        //*********************************************************************
+        friend type_def operator /(const type_def& lhs, const type_def& rhs)
+        {
+            return type_def(lhs.value / rhs.value);
+        }
+
         //*********************************************************************
         friend bool operator <(const type_def& lhs, const type_def& rhs)
         {