+
+TEST(ApplyTuple, UncurryCopyMove) {
+ std::string separator = "================================\n";
+ auto formatRow = folly::uncurry([=](std::string a, std::string b) {
+ // capture separator by copy
+ return separator + a + "\n" + b + "\n" + separator;
+ });
+ auto row = std::make_tuple("hello", "world");
+ auto expected = separator + "hello\nworld\n" + separator;
+ EXPECT_EQ(expected, formatRow(row));
+ auto formatRowCopy = formatRow;
+ EXPECT_EQ(expected, formatRowCopy(row));
+ auto formatRowMove = std::move(formatRow);
+ EXPECT_EQ(expected, formatRowMove(row));
+
+ // capture value moved out from formatRow
+ EXPECT_NE(expected, formatRow(row));
+}
+
+TEST(ApplyTuple, Uncurry) {
+ EXPECT_EQ(42, folly::uncurry([](int x, int y) {
+ return x * y;
+ })(std::pair<int, int>(6, 7)));
+ EXPECT_EQ(42, folly::uncurry([](int&& x, int&& y) {
+ return x * y;
+ })(std::pair<int&&, int&&>(6, 7)));
+ EXPECT_EQ(42, folly::uncurry([](int&& x, int&& y) {
+ return x * y;
+ })(std::pair<int&&, int&&>(6, 7)));
+
+ std::string long1 = "a long string exceeding small string size";
+ std::string long2 = "and here is another one!";
+ std::string expected = long1 + long2;
+
+ auto cat = folly::uncurry(
+ [](std::string a, std::string b) { return std::move(a) + std::move(b); });
+
+ EXPECT_EQ(expected, cat(std::make_pair(long1, long2)));
+ EXPECT_FALSE(long1.empty());
+ EXPECT_FALSE(long2.empty());
+ EXPECT_EQ(expected, cat(std::tie(long1, long2)));
+ EXPECT_FALSE(long1.empty());
+ EXPECT_FALSE(long2.empty());
+ EXPECT_EQ(
+ expected, cat(std::forward_as_tuple(std::move(long1), std::move(long2))));
+ EXPECT_TRUE(long1.empty());
+ EXPECT_TRUE(long2.empty());
+}
+
+TEST(ApplyTuple, UncurryStdFind) {
+ std::vector<std::pair<int, int>> v{{1, 9}, {2, 8}, {3, 7}, {4, 6}, {5, 5}};
+ EXPECT_EQ(
+ 3, std::count_if(v.begin(), v.end(), folly::uncurry([](int a, int b) {
+ return b % a == 0;
+ })));
+}