Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 96 insertions, 0 deletions

diff --git a/src/boost/libs/hof/example/print.cpp b/src/boost/libs/hof/example/print.cpp
new file mode 100644
index 00000000..0149c870
--- /dev/null
+++ b/src/boost/libs/hof/example/print.cpp
@@ -0,0 +1,96 @@
+/*=============================================================================
+    Copyright (c) 2017 Paul Fultz II
+    print.cpp
+    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)
+==============================================================================*/
+/*=============================================================================
+    Copyright (c) 2016 Paul Fultz II
+    print.cpp
+    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 "example.h"
+
+using namespace boost::hof;
+
+// ADL Lookup for ranges
+namespace adl {
+
+using std::begin;
+using std::end;
+
+template<class R>
+auto adl_begin(R&& r) BOOST_HOF_RETURNS(begin(r));
+template<class R>
+auto adl_end(R&& r) BOOST_HOF_RETURNS(end(r));
+}
+
+// Iterate over a tuple
+BOOST_HOF_STATIC_LAMBDA_FUNCTION(for_each_tuple) = [](const auto& sequence, auto f)
+{
+    return unpack(proj(f))(sequence);
+};
+
+#ifdef _MSC_VER
+// On MSVC, trailing decltype doesn't work with generic lambdas, so seperate
+// functions can be used instead.
+template<class Self, class T>
+auto print_with_cout(Self, const T& x) -> decltype(std::cout << x, void())
+{
+    std::cout << x << std::endl;
+}
+
+template<class Self, class T>
+auto print_with_range(Self self, const T& range) -> decltype(self(*adl::adl_begin(range)), void())
+{
+    for(const auto& x:range) self(x);
+}
+
+template<class Self, class T>
+auto print_with_tuple(Self self, const T& tuple) -> decltype(for_each_tuple(tuple, self), void())
+{
+    for_each_tuple(tuple, self);
+}
+
+// Recursively print everything
+BOOST_HOF_STATIC_FUNCTION(simple_print) = fix(first_of(
+    BOOST_HOF_LIFT(print_with_cout),
+    BOOST_HOF_LIFT(print_with_range),
+    BOOST_HOF_LIFT(print_with_tuple)
+));
+#else
+// Recursively print everything
+BOOST_HOF_STATIC_LAMBDA_FUNCTION(simple_print) = fix(first_of(
+    [](auto, const auto& x) -> decltype(std::cout << x, void())
+    {
+        std::cout << x << std::endl;
+    },
+    [](auto self, const auto& range) -> decltype(self(*adl::adl_begin(range)), void())
+    {
+        for(const auto& x:range) self(x);
+    },
+    [](auto self, const auto& tuple) -> decltype(for_each_tuple(tuple, self), void())
+    {
+        for_each_tuple(tuple, self);
+    }
+));
+#endif
+
+// Make print function varidiac
+BOOST_HOF_STATIC_LAMBDA_FUNCTION(print) = proj(simple_print);
+
+int main()
+{
+    print(5, "Hello world");
+    print(5);
+    std::vector<int> v = { 1, 2, 3, 4 };
+    print(v);
+
+    auto t = std::make_tuple(1, 2, 3, 4);
+    print(t);
+
+    auto m = std::make_tuple(3, v, t);
+    print(m);
+}