1 files changed, 23 insertions, 0 deletions
diff --git a/src/boost/libs/hana/example/optional/monad.cpp b/src/boost/libs/hana/example/optional/monad.cpp
new file mode 100644
index 000000000..2be7821a6
--- /dev/null
+++ b/src/boost/libs/hana/example/optional/monad.cpp
@@ -0,0 +1,23 @@
+// Copyright Louis Dionne 2013-2017
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+#include <boost/hana/assert.hpp>
+#include <boost/hana/chain.hpp>
+#include <boost/hana/config.hpp>
+#include <boost/hana/equal.hpp>
+#include <boost/hana/flatten.hpp>
+#include <boost/hana/optional.hpp>
+namespace hana = boost::hana;
+
+
+int main() {
+    BOOST_HANA_CONSTEXPR_LAMBDA auto inc = [](auto x) {
+        return hana::just(x + 1);
+    };
+
+    BOOST_HANA_CONSTEXPR_CHECK(hana::chain(hana::just(1), inc) == hana::just(2));
+    BOOST_HANA_CONSTANT_CHECK(hana::chain(hana::nothing, inc) == hana::nothing);
+
+    BOOST_HANA_CONSTEXPR_CHECK(hana::flatten(hana::just(hana::just(2))) == hana::just(2));
+}