Add llvm::apply to STLExtras.
This is equivalent to the C++14 std::apply(). Since we are not
using C++14 yet, this allows us to still make use of apply anyway.
Differential revision: https://reviews.llvm.org/D25100
llvm-svn: 283779
diff --git a/llvm/unittests/ADT/STLExtrasTest.cpp b/llvm/unittests/ADT/STLExtrasTest.cpp
index db344bc..8675f6d 100644
--- a/llvm/unittests/ADT/STLExtrasTest.cpp
+++ b/llvm/unittests/ADT/STLExtrasTest.cpp
@@ -192,4 +192,49 @@
EXPECT_EQ(0, Moves);
EXPECT_EQ(0, Destructors);
}
+
+TEST(STLExtrasTest, ApplyTuple) {
+ auto T = std::make_tuple(1, 3, 7);
+ auto U = llvm::apply(
+ [](int A, int B, int C) { return std::make_tuple(A - B, B - C, C - A); },
+ T);
+
+ EXPECT_EQ(-2, std::get<0>(U));
+ EXPECT_EQ(-4, std::get<1>(U));
+ EXPECT_EQ(6, std::get<2>(U));
+
+ auto V = llvm::apply(
+ [](int A, int B, int C) {
+ return std::make_tuple(std::make_pair(A, char('A' + A)),
+ std::make_pair(B, char('A' + B)),
+ std::make_pair(C, char('A' + C)));
+ },
+ T);
+
+ EXPECT_EQ(std::make_pair(1, 'B'), std::get<0>(V));
+ EXPECT_EQ(std::make_pair(3, 'D'), std::get<1>(V));
+ EXPECT_EQ(std::make_pair(7, 'H'), std::get<2>(V));
+}
+
+class apply_variadic {
+ static int apply_one(int X) { return X + 1; }
+ static char apply_one(char C) { return C + 1; }
+ static StringRef apply_one(StringRef S) { return S.drop_back(); }
+
+public:
+ template <typename... Ts>
+ auto operator()(Ts &&... Items)
+ -> decltype(std::make_tuple(apply_one(Items)...)) {
+ return std::make_tuple(apply_one(Items)...);
+ }
+};
+
+TEST(STLExtrasTest, ApplyTupleVariadic) {
+ auto Items = std::make_tuple(1, llvm::StringRef("Test"), 'X');
+ auto Values = apply(apply_variadic(), Items);
+
+ EXPECT_EQ(2, std::get<0>(Values));
+ EXPECT_EQ("Tes", std::get<1>(Values));
+ EXPECT_EQ('Y', std::get<2>(Values));
+}
}