Add use_default to Core

doc/core.qbk

@@ -58,3 +58,4 @@ criteria for inclusion is that the utility component be:
 [include swap.qbk]
 [include typeinfo.qbk]
 [include uncaught_exceptions.qbk]
+[include use_default.qbk]

doc/lightweight_test.qbk

@@ -1,7 +1,7 @@
 [/
   Copyright 2010, 2011 Beman Dawes
   Copyright 2013 Ion Gaztanaga
-  Copyright 2014, 2017 Peter Dimov
+  Copyright 2014-2019 Peter Dimov
   Copyright 2017 Kohei Takahashi
 
   Distributed under the Boost Software License, Version 1.0.
@@ -253,6 +253,7 @@ return a boolean value.
 ``
 #define BOOST_TEST_TRAIT_TRUE((Trait)) /*unspecified*/
 #define BOOST_TEST_TRAIT_FALSE((Trait)) /*unspecified*/
+#define BOOST_TEST_TRAIT_SAME(Type1, Type2) /*unspecified*/
 ``
 
 [endsect]
@@ -280,6 +281,20 @@ message containing `Trait`. Note the double set of parentheses.
 
 [endsect]
 
+[section BOOST_TEST_TRAIT_SAME]
+
+``
+BOOST_TEST_TRAIT_SAME(Type1, Type2)
+``
+
+If the two types are not the same, increases the error count and outputs a
+message containing them. This macro requires that the compiler supports
+variadic macros and `__VA_ARGS__`. (Note that unlike `BOOST_TEST_TRAIT_TRUE`
+and `BOOST_TEST_TRAIT_FALSE`, this macro only requires a single set of
+parentheses.)
+
+[endsect]
+
 [section Example]
 
 ``
@@ -297,6 +312,8 @@ int main()
 {
     BOOST_TEST_TRAIT_TRUE(( is_same<X<int, long>::type, int> ));
 
+    BOOST_TEST_TRAIT_SAME( X<int, long>::type, int );
+
     return boost::report_errors();
 }
 ``

doc/use_default.qbk

@@ -0,0 +1,47 @@
+[/
+Copyright 2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+]
+
+[section:use_default use_default]
+
+[section Overview]
+
+The header <boost/core/use_default.hpp> provides the type `boost::use_default`
+which is used by other Boost libraries as a sentinel type in a templates to
+indicate defaults.
+
+[endsect]
+
+[section Example]
+
+```
+template<class Derived, class Base,
+   class Value = boost::use_default,
+   class CategoryOrTraversal = boost::use_default,
+   class Reference = boost::use_default,
+   class Difference = boost::use_default>
+class iterator_adaptor;
+
+template<class Value>
+class node_iterator
+    : public iterator_adaptor<node_iterator<Value>, Value*,
+        boost::use_default, boost::forward_traversal_tag>;
+```
+
+[endsect]
+
+[section Reference]
+
+```
+namespace boost {
+  struct use_default { };
+}
+```
+
+[endsect]
+
+[endsect]

include/boost/core/checked_delete.hpp

@@ -7,6 +7,8 @@
 # pragma once
 #endif
 
+#include <boost/config.hpp>
+
 //
 //  boost/checked_delete.hpp
 //
@@ -26,7 +28,7 @@ namespace boost
 
 // verify that types are complete for increased safety
 
-template<class T> inline void checked_delete(T * x)
+template<class T> inline void checked_delete(T * x) BOOST_NOEXCEPT
 {
     // intentionally complex - simplification causes regressions
     typedef char type_must_be_complete[ sizeof(T)? 1: -1 ];
@@ -34,7 +36,7 @@ template<class T> inline void checked_delete(T * x)
     delete x;
 }
 
-template<class T> inline void checked_array_delete(T * x)
+template<class T> inline void checked_array_delete(T * x) BOOST_NOEXCEPT
 {
     typedef char type_must_be_complete[ sizeof(T)? 1: -1 ];
     (void) sizeof(type_must_be_complete);
@@ -46,7 +48,7 @@ template<class T> struct checked_deleter
     typedef void result_type;
     typedef T * argument_type;
 
-    void operator()(T * x) const
+    void operator()(T * x) const BOOST_NOEXCEPT
     {
         // boost:: disables ADL
         boost::checked_delete(x);
@@ -58,7 +60,7 @@ template<class T> struct checked_array_deleter
     typedef void result_type;
     typedef T * argument_type;
 
-    void operator()(T * x) const
+    void operator()(T * x) const BOOST_NOEXCEPT
     {
         boost::checked_array_delete(x);
     }

include/boost/core/lightweight_test_trait.hpp

@@ -9,7 +9,7 @@
 
 // boost/core/lightweight_test_trait.hpp
 //
-// BOOST_TEST_TRAIT_TRUE, BOOST_TEST_TRAIT_FALSE
+// BOOST_TEST_TRAIT_TRUE, BOOST_TEST_TRAIT_FALSE, BOOST_TEST_TRAIT_SAME
 //
 // Copyright 2014 Peter Dimov
 //
@@ -19,6 +19,7 @@
 
 #include <boost/core/lightweight_test.hpp>
 #include <boost/core/typeinfo.hpp>
+#include <boost/core/is_same.hpp>
 
 namespace boost
 {
@@ -46,11 +47,37 @@ template< class T > inline void test_trait_impl( char const * trait, void (*)( T
     }
 }
 
+template<class T> inline bool test_trait_same_impl_( T )
+{
+    return T::value;
+}
+
+template<class T1, class T2> inline void test_trait_same_impl( char const * types,
+  boost::core::is_same<T1, T2> same, char const * file, int line, char const * function )
+{
+    if( test_trait_same_impl_( same ) )
+    {
+        test_results();
+    }
+    else
+    {
+        BOOST_LIGHTWEIGHT_TEST_OSTREAM
+            << file << "(" << line << "): test 'is_same<" << types << ">'"
+            << " failed in function '" << function
+            << "' ('" << boost::core::demangled_name( BOOST_CORE_TYPEID(T1) )
+            << "' != '" << boost::core::demangled_name( BOOST_CORE_TYPEID(T2) ) << "')"
+            << std::endl;
+
+        ++test_results().errors();
+    }
+}
+
 } // namespace detail
 
 } // namespace boost
 
 #define BOOST_TEST_TRAIT_TRUE(type) ( ::boost::detail::test_trait_impl(#type, (void(*)type)0, true, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION) )
 #define BOOST_TEST_TRAIT_FALSE(type) ( ::boost::detail::test_trait_impl(#type, (void(*)type)0, false, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION) )
+#define BOOST_TEST_TRAIT_SAME(...) ( ::boost::detail::test_trait_same_impl(#__VA_ARGS__, ::boost::core::is_same<__VA_ARGS__>(), __FILE__, __LINE__, BOOST_CURRENT_FUNCTION) )
 
 #endif // #ifndef BOOST_CORE_LIGHTWEIGHT_TEST_TRAIT_HPP

include/boost/core/use_default.hpp

@@ -0,0 +1,17 @@
+/*
+Copyright 2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BOOST_CORE_USE_DEFAULT_HPP
+#define BOOST_CORE_USE_DEFAULT_HPP
+
+namespace boost {
+
+struct use_default { };
+
+} /* boost */
+
+#endif

test/Jamfile.v2

@@ -76,6 +76,8 @@ run lightweight_test_lt_le_test.cpp ;
 run lightweight_test_gt_ge_test.cpp ;
 run lightweight_test_eq_nullptr.cpp ;
 run lightweight_test_test3.cpp ;
+run lightweight_test_test4.cpp ;
+run lightweight_test_test5.cpp ;
 
 run-fail lightweight_test_fail.cpp ;
 run-fail lightweight_test_fail2.cpp ;
@@ -126,10 +128,13 @@ run exchange_move_test.cpp ;
 
 run empty_value_test.cpp ;
 run empty_value_size_test.cpp ;
+run empty_value_final_test.cpp ;
 
 run quick_exit_test.cpp ;
 run-fail quick_exit_fail.cpp ;
 
+compile use_default_test.cpp ;
+
 lib lib_typeid : lib_typeid.cpp : <link>shared:<define>LIB_TYPEID_DYN_LINK=1 ;
 
 run test_lib_typeid.cpp lib_typeid : : : <link>shared : test_lib_typeid_shared ;

test/empty_value_final_test.cpp

@@ -0,0 +1,62 @@
+/*
+Copyright 2018 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#include <boost/core/empty_value.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+#if !defined(BOOST_NO_CXX11_FINAL)
+class type final {
+public:
+    explicit type(int count)
+        : value_(count) { }
+    int value() const {
+        return value_ + 1;
+    }
+    int value() {
+        return value_ + 2;
+    }
+private:
+    int value_;
+};
+
+struct empty final {
+    int value() const {
+        return 1;
+    }
+    int value() {
+        return 2;
+    }
+};
+
+void test_type()
+{
+    const boost::empty_value<type> v1(boost::empty_init_t(), 3);
+    BOOST_TEST(v1.get().value() == 4);
+    boost::empty_value<type> v2(boost::empty_init_t(), 3);
+    BOOST_TEST(v2.get().value() == 5);
+}
+
+void test_empty()
+{
+    const boost::empty_value<empty> v1 = boost::empty_init_t();
+    BOOST_TEST(v1.get().value() == 1);
+    boost::empty_value<empty> v2;
+    BOOST_TEST(v2.get().value() == 2);
+}
+
+int main()
+{
+    test_type();
+    test_empty();
+    return boost::report_errors();
+}
+#else
+int main()
+{
+    return 0;
+}
+#endif

test/empty_value_test.cpp

@@ -9,67 +9,63 @@ Distributed under the Boost Software License, Version 1.0.
 #include <boost/core/lightweight_test.hpp>
 
 struct empty {
-    operator bool() const {
-        return false;
+    int value() const {
+        return 1;
     }
-    operator bool() {
-        return true;
+    int value() {
+        return 2;
     }
 };
 
 class type {
 public:
-    type()
-        : value_(false) { }
-    explicit type(bool value)
-        : value_(value) { }
-    operator bool() const {
-        return value_;
+    explicit type(int count)
+        : value_(count) { }
+    int value() const {
+        return value_ + 1;
+    }
+    int value() {
+        return value_ + 2;
     }
 private:
-    bool value_;
+    int value_;
 };
 
-void test_bool()
+void test_int()
 {
-    const boost::empty_value<bool> v1(boost::empty_init_t(), true);
-    BOOST_TEST(v1.get());
-    boost::empty_value<bool> v2 = boost::empty_init_t();
-    BOOST_TEST(!v2.get());
+    const boost::empty_value<int> v1(boost::empty_init_t(), 7);
+    BOOST_TEST(v1.get() == 7);
+    boost::empty_value<int> v2 = boost::empty_init_t();
+    BOOST_TEST(v2.get() == 0);
     v2 = v1;
-    BOOST_TEST(v2.get());
-    v2.get() = false;
-    BOOST_TEST(!v2.get());
+    BOOST_TEST(v2.get() == 7);
+    v2.get() = 8;
+    BOOST_TEST(v2.get() == 8);
 }
 
 void test_empty()
 {
-    empty e;
-    const boost::empty_value<empty> v1(boost::empty_init_t(), e);
-    BOOST_TEST(!v1.get());
+    const boost::empty_value<empty> v1 = boost::empty_init_t();
+    BOOST_TEST(v1.get().value() == 1);
     boost::empty_value<empty> v2;
-    BOOST_TEST(v2.get());
-    v2 = v1;
-    BOOST_TEST(v2.get());
-    v2.get() = empty();
-    BOOST_TEST(v2.get());
+    BOOST_TEST(v2.get().value() == 2);
 }
 
 void test_type()
 {
-    const boost::empty_value<type> v1(boost::empty_init_t(), true);
-    BOOST_TEST(v1.get());
-    boost::empty_value<type> v2;
-    BOOST_TEST(!v2.get());
+    const boost::empty_value<type> v1(boost::empty_init_t(), 2);
+    BOOST_TEST(v1.get().value() == 3);
+    boost::empty_value<type> v2(boost::empty_init_t(), 3);
+    BOOST_TEST(v2.get().value() == 5);
     v2 = v1;
-    BOOST_TEST(v2.get());
-    v2.get() = type();
-    BOOST_TEST(!v2.get());
+    BOOST_TEST(v2.get().value() == 4);
+    v2.get() = type(4);
+    BOOST_TEST(v2.get().value() == 6);
 }
 
 int main()
 {
-    test_bool();
+    test_int();
     test_empty();
     test_type();
     return boost::report_errors();

test/lightweight_test_test4.cpp

@@ -0,0 +1,36 @@
+//
+// Test for BOOST_TEST_TRAIT_SAME
+//
+// Copyright 2014, 2019 Peter Dimov
+//
+// Distributed under 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
+//
+
+#include <boost/core/lightweight_test_trait.hpp>
+
+struct X
+{
+    typedef int type;
+};
+
+template<class T1, class T2> struct Y
+{
+    typedef T1 type;
+};
+
+int main()
+{
+    BOOST_TEST_TRAIT_SAME(X, X);
+    BOOST_TEST_TRAIT_SAME(void, void);
+    BOOST_TEST_TRAIT_SAME(char[1], char[1]);
+    BOOST_TEST_TRAIT_SAME(char[], char[]);
+    BOOST_TEST_TRAIT_SAME(void(), void());
+    BOOST_TEST_TRAIT_SAME(X::type, X::type);
+    BOOST_TEST_TRAIT_SAME(X::type, Y<int, float>::type);
+    BOOST_TEST_TRAIT_SAME(Y<int, float>, Y<int, float>);
+    BOOST_TEST_TRAIT_SAME(Y<void, float>::type, void);
+
+    return boost::report_errors();
+}

test/lightweight_test_test5.cpp

@@ -0,0 +1,37 @@
+//
+// Negative test for BOOST_TEST_TRAIT_SAME
+//
+// Copyright 2014, 2019 Peter Dimov
+//
+// Distributed under 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
+//
+
+#include <boost/core/lightweight_test_trait.hpp>
+
+struct X
+{
+    typedef int type;
+};
+
+template<class T1, class T2> struct Y
+{
+    typedef T1 type;
+};
+
+int main()
+{
+    BOOST_TEST_TRAIT_SAME(char[1], char[2]);
+    BOOST_TEST_TRAIT_SAME(char[1], char[]);
+    BOOST_TEST_TRAIT_SAME(char[1], char*);
+    BOOST_TEST_TRAIT_SAME(void(), void(int));
+    BOOST_TEST_TRAIT_SAME(void(), void(*)());
+    BOOST_TEST_TRAIT_SAME(X, void);
+    BOOST_TEST_TRAIT_SAME(X::type, void);
+    BOOST_TEST_TRAIT_SAME(X, Y<void, void>);
+    BOOST_TEST_TRAIT_SAME(X::type, Y<float, int>::type);
+    BOOST_TEST_TRAIT_SAME(Y<int, float>, Y<int, double>);
+
+    return boost::report_errors() == 10;
+}

test/use_default_test.cpp

@@ -0,0 +1,15 @@
+/*
+Copyright 2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+
+#include <boost/core/use_default.hpp>
+
+template<class, class = boost::use_default>
+struct type { };
+
+template class type<int>;
+template class type<void, boost::use_default>;