From 3c017bfa105c792416f0374c9f8e740905825ae0 Mon Sep 17 00:00:00 2001
From: Alexander Ryabykin <rav.thunderbird@gmail.com>
Date: Sat, 2 Jul 2016 15:24:10 +0300
Subject: [PATCH] constexpr operators

---
 include/gsl.h | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/include/gsl.h b/include/gsl.h
index ad064ba..8db781b 100644
--- a/include/gsl.h
+++ b/include/gsl.h
@@ -101,8 +101,8 @@ public:
     not_null(std::nullptr_t) = delete;
     not_null(int) = delete;
     not_null<T>& operator=(std::nullptr_t) = delete;
-	not_null<T>& operator=(int) = delete;
-    
+    not_null<T>& operator=(int) = delete;
+
     T get() const {
 #ifdef _MSC_VER
         __assume(ptr_ != nullptr);
@@ -110,11 +110,16 @@ public:
         return ptr_;
     } // the assume() should help the optimizer
 
-    operator T() const {  return get(); }
+    operator T() const { return get(); }
     T operator->() const { return get(); }
 
-	bool operator==(const T& rhs) const { return ptr_ == rhs; }
-	bool operator!=(const T& rhs) const { return !(*this == rhs); }
+    bool operator==(const T& rhs) const { return ptr_ == rhs; }
+    bool operator!=(const T& rhs) const { return !(*this == rhs); }
+
+    constexpr bool operator==(std::nullptr_t) const { return false; }
+    constexpr bool operator!=(std::nullptr_t) const { return true; }
+
+    constexpr operator bool() const { return true; }
 private:
     T ptr_;