Adding upstream version 14.2.21.upstream/14.2.21upstream

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

1 files changed, 81 insertions, 0 deletions

diff --git a/src/boost/libs/hof/example/in.cpp b/src/boost/libs/hof/example/in.cpp
new file mode 100644
index 00000000..a8954140
--- /dev/null
+++ b/src/boost/libs/hof/example/in.cpp
@@ -0,0 +1,81 @@
+/*=============================================================================
+    Copyright (c) 2017 Paul Fultz II
+    in.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
+    in.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;
+
+#ifdef _MSC_VER
+template<class R, class T>
+auto member_find(const R& r, const T& x) BOOST_HOF_RETURNS(r.find(x));
+#endif
+
+// Function to find an iterator using a containers built-in find if available
+BOOST_HOF_STATIC_LAMBDA_FUNCTION(find_iterator) = first_of(
+    [](const std::string& s, const auto& x)
+    {
+        auto index = s.find(x);
+        if (index == std::string::npos) return s.end();
+        else return s.begin() + index;
+    },
+#ifdef _MSC_VER
+    // On MSVC, trailing decltype doesn't work with generic lambdas, so a
+    // seperate function can be used instead.
+    BOOST_HOF_LIFT(member_find),
+#else
+    [](const auto& r, const auto& x) BOOST_HOF_RETURNS(r.find(x)),
+#endif
+    [](const auto& r, const auto& x)
+    {
+        using std::begin;
+        using std::end;
+        return std::find(begin(r), end(r), x);
+    }
+);
+// Implement an infix `in` operator to check if a range contains an element
+BOOST_HOF_STATIC_LAMBDA_FUNCTION(in) = infix(
+    [](const auto& x, const auto& r)
+    {
+        using std::end;
+        return find_iterator(r, x) != end(r);
+    }
+);
+// Negate version of `in`
+BOOST_HOF_STATIC_LAMBDA_FUNCTION(not_in) = infix(compose(not _, in));
+
+int main()
+{
+    // Check if vector contains element
+    std::vector<int> numbers = { 1, 2, 3, 4, 5 };
+    if (5 <in> numbers) std::cout << "Yes" << std::endl;
+
+    // Check if string contains element
+    std::string s = "hello world";
+    if ("hello" <in> s) std::cout << "Yes" << std::endl;
+
+    // Check if map contains element
+    std::map<int, std::string> number_map = {
+        { 1, "1" },
+        { 2, "2" },
+        { 3, "3" },
+        { 4, "4" }
+    };
+
+    if (4 <in> number_map) std::cout << "Yes" << std::endl;
+
+    // Check if map doesn't contains element
+    if (not (8 <in> numbers)) std::cout << "No" << std::endl;
+    if (8 <not_in> numbers) std::cout << "No" << std::endl;
+
+}
+