From 52d7429473371b40b0727c540240ea6bb6ff36d2 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Mon, 26 Sep 2022 21:01:49 +0300
Subject: [PATCH] Add value_type, error_type typedefs to result. Refs #93.

---
 include/boost/system/result.hpp | 10 ++++++++++
 test/CMakeLists.txt             |  1 +
 test/Jamfile.v2                 |  1 +
 test/result_typedefs.cpp        | 22 ++++++++++++++++++++++
 4 files changed, 34 insertions(+)
 create mode 100644 test/result_typedefs.cpp

diff --git a/include/boost/system/result.hpp b/include/boost/system/result.hpp
index 2e0ddc3..f3d9cbd 100644
--- a/include/boost/system/result.hpp
+++ b/include/boost/system/result.hpp
@@ -95,6 +95,11 @@ private:
 
     variant2::variant<T, E> v_;
 
+public:
+
+    using value_type = T;
+    using error_type = E;
+
 public:
 
     // constructors
@@ -444,6 +449,11 @@ private:
 
     variant2::variant<variant2::monostate, E> v_;
 
+public:
+
+    using value_type = void;
+    using error_type = E;
+
 public:
 
     // constructors
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 55efd27..de8c636 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -149,3 +149,4 @@ boost_test(TYPE run SOURCES result_range_for.cpp)
 boost_test(TYPE run SOURCES result_value_construct2.cpp)
 boost_test(TYPE run SOURCES result_error_construct2.cpp)
 boost_test(TYPE run SOURCES result_convert_construct.cpp)
+boost_test(TYPE run SOURCES result_typedefs.cpp)
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index d110d39..ce82929 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -180,3 +180,4 @@ run result_value_construct2.cpp : : : $(CPP11) ;
 run result_error_construct2.cpp : : : $(CPP11) ;
 run result_errc_construct.cpp : : : $(CPP11) ;
 run result_convert_construct.cpp : : : $(CPP11) ;
+run result_typedefs.cpp : : : $(CPP11) ;
diff --git a/test/result_typedefs.cpp b/test/result_typedefs.cpp
new file mode 100644
index 0000000..6a9a63d
--- /dev/null
+++ b/test/result_typedefs.cpp
@@ -0,0 +1,22 @@
+// Copyright 2022 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/system/result.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+using namespace boost::system;
+
+struct X {};
+
+int main()
+{
+    BOOST_TEST_TRAIT_SAME( result<int>::value_type, int );
+    BOOST_TEST_TRAIT_SAME( result<X>::value_type, X );
+    BOOST_TEST_TRAIT_SAME( result<void>::value_type, void );
+
+    BOOST_TEST_TRAIT_SAME( result<int>::error_type, error_code );
+    BOOST_TEST_TRAIT_SAME( result<int, X>::error_type, X );
+
+    return boost::report_errors();
+}