Added func value_or_eval()

test/Jamfile.v2

@@ -42,5 +42,6 @@ import testing ;
     [ compile-fail optional_test_ref_fail_assign_from_Trefref.cpp ]
     [ compile-fail optional_test_ref_fail_assign_from_Urefref.cpp ]
     [ compile-fail optional_test_fail_explicit_convert_in_value_or.cpp ]
+    [ compile-fail optional_test_fail_explicit_convert_in_value_or_call.cpp ]
   ;
 }

test/optional_test_fail_explicit_convert_in_value_or_call.cpp

@@ -0,0 +1,34 @@
+// 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/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+//
+#include "boost/optional.hpp"
+
+//
+// THIS TEST SHOULD FAIL TO COMPILE
+//
+
+struct U
+{};
+
+struct T
+{
+  explicit T(U const&) {}
+};
+
+U get_U() { return U(); }
+
+
+void test_verifying_the_implicit_conversion_to_bool()
+{
+  boost::optional<T> opt;
+  opt.value_or_eval(get_U);
+}
+

test/optional_test_value_access.cpp

@@ -128,6 +128,73 @@ void test_function_value_or()
     BOOST_CHECK(FatToIntConverter::conversions == 1);
 }
 
+
+struct FunM
+{
+    int operator()() { return 5; }
+};
+
+struct FunC
+{
+    int operator()() const { return 6; }
+};
+
+int funP ()
+{
+    return 7;
+}
+
+int throw_()
+{
+    throw int();
+}
+
+void test_function_value_or_call()
+{
+    optional<int> o1 = 1;
+    optional<int> oN;
+    FunM funM;
+    FunC funC;
+    
+    BOOST_CHECK(o1.value_or_eval(funM) == 1);
+    BOOST_CHECK(oN.value_or_eval(funM) == 5);
+    BOOST_CHECK(o1.value_or_eval(FunM()) == 1);
+    BOOST_CHECK(oN.value_or_eval(FunM()) == 5);
+    
+    BOOST_CHECK(o1.value_or_eval(funC) == 1);
+    BOOST_CHECK(oN.value_or_eval(funC) == 6);
+    BOOST_CHECK(o1.value_or_eval(FunC()) == 1);
+    BOOST_CHECK(oN.value_or_eval(FunC()) == 6);
+    
+    BOOST_CHECK(o1.value_or_eval(funP) == 1);
+    BOOST_CHECK(oN.value_or_eval(funP) == 7);
+    
+#ifndef BOOST_NO_CXX11_LAMBDAS
+    BOOST_CHECK(o1.value_or_eval([](){return 8;}) == 1);
+    BOOST_CHECK(oN.value_or_eval([](){return 8;}) == 8);
+#endif
+
+    try
+    {
+      BOOST_CHECK(o1.value_or_eval(throw_) == 1);
+    }
+    catch(...)
+    {
+      BOOST_CHECK(false);
+    }
+    
+    try
+    {
+      BOOST_CHECK(oN.value_or_eval(throw_) == 1);
+      BOOST_CHECK(false);
+    }
+    catch(...)
+    {
+      BOOST_CHECK(true);
+    }
+}
+
+
 #ifndef BOOST_NO_CXX11_REF_QUALIFIERS
 struct MoveOnly
 {
@@ -144,15 +211,22 @@ optional<MoveOnly> makeMoveOnly()
     return MoveOnly(1);
 }
 
+MoveOnly moveOnlyDefault()
+{
+    return MoveOnly(1);
+}
+
 // compile-time test
 void test_move_only_getters()
 {
     MoveOnly m1 = *makeMoveOnly();
     MoveOnly m2 = makeMoveOnly().value();
     MoveOnly m3 = makeMoveOnly().value_or(MoveOnly(1));
+    MoveOnly m4 = makeMoveOnly().value_or_eval(moveOnlyDefault);
     unused_variable(m1);
     unused_variable(m2);
     unused_variable(m3);
+    unused_variable(m4);
 }
 
 #endif
@@ -163,6 +237,7 @@ int test_main( int, char* [] )
   {
     test_function_value();
     test_function_value_or();
+    test_function_value_or_call();
   }
   catch ( ... )
   {