From 03bed6e0dc6959fc06c4cba24b07d7b985b9237c Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@gmail.com>
Date: Fri, 27 Dec 2019 15:10:36 +0100
Subject: new_type: implement equality operators

---
 include/newtype/new_type.hpp | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/include/newtype/new_type.hpp b/include/newtype/new_type.hpp
index 0dc0ff6..68a22dd 100644
--- a/include/newtype/new_type.hpp
+++ b/include/newtype/new_type.hpp
@@ -107,7 +107,7 @@ namespace nt
     /**
      * Convert this instance into the equivalent base type value
      *
-     * @note This overload participates only in overload resolution if the derication clause of this @p new_type contains
+     * @note This overload participates only in overload resolution if the derivation clause of this @p new_type contains
      * nt::ImplicitConversion
      */
     template<typename NewType = new_type, std::enable_if_t<NewType::derivations(nt::ImplicitConversion)> * = nullptr>
@@ -119,7 +119,7 @@ namespace nt
     /**
      * Convert this instance into the equivalent base type value
      *
-     * @note This overload participates only in overload resolution if the derication clause of this @p new_type does not contain
+     * @note This overload participates only in overload resolution if the derivation clause of this @p new_type does not contain
      * nt::ImplicitConversion
      */
     template<typename NewType = new_type, std::enable_if_t<!NewType::derivations(nt::ImplicitConversion)> * = nullptr>
@@ -129,6 +129,26 @@ namespace nt
     }
   };
 
+  /**
+   * Compare two objects for equality
+   */
+  template<typename BaseType, typename TagType, auto DerivationClause>
+  auto constexpr operator==(new_type<BaseType, TagType, DerivationClause> const & lhs,
+                            new_type<BaseType, TagType, DerivationClause> const & rhs) noexcept(noexcept(lhs.decay() == rhs.decay())) -> bool
+  {
+    return lhs.decay() == rhs.decay();
+  }
+
+  /**
+   * Compare two objects for non-equality
+   */
+  template<typename BaseType, typename TagType, auto DerivationClause>
+  auto constexpr operator!=(new_type<BaseType, TagType, DerivationClause> const & lhs,
+                            new_type<BaseType, TagType, DerivationClause> const & rhs) noexcept(noexcept(!(lhs == rhs))) -> bool
+  {
+    return !(lhs == rhs);
+  }
+
 }  // namespace nt
 
 #endif
-- 
cgit v1.2.3