Member fun value() that throws on uninitialized

include/boost/bad_optional_access.hpp

@@ -0,0 +1,28 @@
+// Copyright (C) 2014, Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+//
+#ifndef BOOST_BAD_OPTIONAL_ACCESS_22MAY2014_HPP
+#define BOOST_BAD_OPTIONAL_ACCESS_22MAY2014_HPP
+
+#include <stdexcept>
+
+namespace boost {
+
+class bad_optional_access : public std::logic_error
+{
+public:
+  explicit bad_optional_access(const std::string& what_arg) : std::logic_error(what_arg) {}
+  explicit bad_optional_access(const char* what_arg) : std::logic_error(what_arg) {}
+};
+
+} // namespace boost
+
+#endif

include/boost/optional/optional.hpp

@@ -23,7 +23,9 @@
 
 #include <boost/config.hpp>
 #include <boost/assert.hpp>
+#include <boost/bad_optional_access.hpp>
 #include <boost/static_assert.hpp>
+#include <boost/throw_exception.hpp>
 #include <boost/type.hpp>
 #include <boost/type_traits/alignment_of.hpp>
 #include <boost/type_traits/has_nothrow_constructor.hpp>
@@ -935,6 +937,22 @@ class optional : public optional_detail::optional_base<T>
     // No-throw
     reference_const_type operator *() const { return this->get() ; }
     reference_type       operator *()       { return this->get() ; }
+    
+    reference_const_type value() const
+      { 
+        if (this->is_initialized())
+          return this->get() ;
+        else
+          throw_exception(bad_optional_access("Attempted to access the value of an uninitialized optional object."));
+      }
+      
+    reference_type value()
+      { 
+        if (this->is_initialized())
+          return this->get() ;
+        else
+          throw_exception(bad_optional_access("Attempted to access the value of an uninitialized optional object."));
+      }
 
     bool operator!() const BOOST_NOEXCEPT { return !this->is_initialized() ; }
     

include/boost/optional/optional_fwd.hpp

@@ -11,11 +11,9 @@
 //
 // Revisions:
 // 10 May 2008 (added swap related forward declaration) Niels Dekker
-// 17 Apr 2014 (added noexcept) Andrzej Krzemienski 
 //
 #ifndef BOOST_OPTIONAL_OPTIONAL_FWD_FLC_19NOV2002_HPP
 #define BOOST_OPTIONAL_OPTIONAL_FWD_FLC_19NOV2002_HPP
-#include <boost/config.hpp>
 
 
 namespace boost {