From f092580a0ed0367aca6c492d74601f53a82dac41 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 9 Feb 2016 19:06:13 +0200
Subject: Implement ==, != operators for optional class template

---
 butl/optional | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

(limited to 'butl/optional')

diff --git a/butl/optional b/butl/optional
index 308302e..00c204a 100644
--- a/butl/optional
+++ b/butl/optional
@@ -40,6 +40,20 @@ namespace butl
     T value_;
     bool null_;
   };
+
+  template <typename T>
+  inline auto
+  operator== (const optional<T>& x, const optional<T>& y) -> decltype (*x == *y)
+  {
+    return static_cast<bool> (x) == static_cast<bool> (y) && (!x || *x == *y);
+  }
+
+  template <typename T>
+  inline auto
+  operator!= (const optional<T>& x, const optional<T>& y) -> decltype (x == y)
+  {
+    return !(x == y);
+  }
 }
 
 #endif // BUTL_OPTIONAL
-- 
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