Support comma operator in subscripting expressions of lambda introducer

loliGothicK · Dec 7, 2020 · 185f30d · 185f30d
1 parent abbe03e
commit 185f30d
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Showing 3 changed files with 54 additions and 13 deletions.
diff --git a/include/mitama/result/result.hpp b/include/mitama/result/result.hpp
@@ -1774,21 +1774,38 @@ class [[nodiscard]] basic_result<_mutability, T, E,
 } // namespace mitama
 
 // MSVC does not implement compound statements (ref: https://stackoverflow.com/q/5291532)
-#if defined(__GNUC__) || defined(__clang__)
+#if defined(__clang__) || defined(__GNUC__)
 #  define MITAMA_CPP_RESULT_TRY_MAY_NOT_PANIC true
-#  define MITAMA_TRY( RESULT )                                         \
-    ({                                                                 \
-        const auto result = RESULT;                                    \
-        if (result.is_err()) {                                         \
-            using Err = mitama::failure_t<decltype(result)::err_type>; \
-            return std::get<Err>(result.into_storage());               \
-        }                                                              \
-        using Ok = mitama::success_t<decltype(result)::ok_type>;       \
-        std::get<Ok>(result.into_storage()).get();                     \
+#  define MITAMA_TRY_IMPL( ... )                                                   \
+    ({                                                                             \
+        auto&& result = [&]()->decltype(auto){ return (__VA_ARGS__); }();          \
+        static_assert(                                                             \
+            ::mitama::is_result_v<::mitama::meta::remove_cvr_t<decltype(result)>>, \
+            "You should pass mitama::result type to this MITAMA_TRY macro."        \
+        );                                                                         \
+        if (result.is_err()) {                                                     \
+            using Err = ::mitama::failure_t<                                       \
+                ::mitama::meta::remove_cvr_t<decltype(result)>::err_type           \
+            >;                                                                     \
+            return ::std::get<Err>(result.into_storage());                         \
+        }                                                                          \
+        using Ok = ::mitama::success_t<                                            \
+            ::mitama::meta::remove_cvr_t<decltype(result)>::ok_type                \
+        >;                                                                         \
+        ::std::get<Ok>(result.into_storage()).get();                               \
     })
+#  ifdef __clang__
+#    define MITAMA_TRY( ... )                                                      \
+      _Pragma("GCC diagnostic push")                                               \
+      _Pragma("GCC diagnostic ignored \"-Wgnu-statement-expression\"")             \
+      MITAMA_TRY_IMPL(__VA_ARGS__)                                                 \
+      _Pragma("GCC diagnostic pop")
+#  else
+#    define MITAMA_TRY( ... ) MITAMA_TRY_IMPL(__VA_ARGS__)
+#  endif
 #else
 #  define MITAMA_CPP_RESULT_TRY_MAY_NOT_PANIC false
-#  define MITAMA_TRY( RESULT ) RESULT.unwrap()
+#  define MITAMA_TRY( ... ) (__VA_ARGS__).unwrap()
 #endif
 
 #endif
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
@@ -17,8 +17,11 @@ message($CMAKE)
 foreach(TEST_NAME ${TEST_NAMES})
   add_executable(${TEST_NAME} ${TEST_NAME}.cpp)
   target_compile_features(${TEST_NAME} PRIVATE cxx_std_17)
-  target_compile_options(${TEST_NAME} PRIVATE -Wall -Wextra -pedantic-errors -ftemplate-backtrace-limit=0)
-  # -Wall -Wextra -Werror -pedantic-errors
+  if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    target_compile_options(${TEST_NAME} PRIVATE -Wall -Wextra -ftemplate-backtrace-limit=0)
+  else()
+    target_compile_options(${TEST_NAME} PRIVATE -Wall -Wextra -pedantic-errors -ftemplate-backtrace-limit=0)
+  endif()
 
   if(APPLE)
     target_compile_definitions(${TEST_NAME} PRIVATE _GNU_SOURCE)

diff --git a/test/result_tests.cpp b/test/result_tests.cpp
@@ -1285,3 +1285,24 @@ TEST_CASE("map & map_err with void", "[result][map][map_err][void]"){
     REQUIRE(y.is_ok() == true);
     REQUIRE(val == 6);
 }
+
+TEST_CASE("MITAMA_TRY", "[result][mitama_try]"){
+    auto func =
+        []() -> result<u32, str> {
+            result<u32, str> a = success(1);
+            u32 b = 2, c = 3;
+            u32 d = MITAMA_TRY(
+                [&a, &b, &c]() -> ::result<u32, str> {
+                    return a.map(
+                        [&b, &c](u32 x) -> u32 { return x + b + c; }
+                    );
+                }()
+            );
+            return success(d);
+        };
+
+    result<u32, str> x = func();
+    REQUIRE(MITAMA_CPP_RESULT_TRY_MAY_NOT_PANIC == true);
+    REQUIRE(x.is_ok() == true);
+    REQUIRE(x.unwrap() == 6);
+}