1 files changed, 31 insertions, 0 deletions
diff --git a/src/boost/libs/hana/example/struct/foldable.cpp b/src/boost/libs/hana/example/struct/foldable.cpp
new file mode 100644
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--- /dev/null
+++ b/src/boost/libs/hana/example/struct/foldable.cpp
@@ -0,0 +1,31 @@
+// 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/define_struct.hpp>
+#include <boost/hana/fold_left.hpp>
+#include <boost/hana/second.hpp>
+namespace hana = boost::hana;
+
+
+struct Kitten {
+    BOOST_HANA_DEFINE_STRUCT(Kitten,
+        (int, extremely_cute),
+        (int, cute),
+        (int, not_so_cute)
+    );
+};
+
+int main() {
+    constexpr Kitten kitten{5, 10, 0};
+
+    BOOST_HANA_CONSTEXPR_CHECK(
+        hana::fold_left(kitten, 0, [](auto total, auto member) {
+            // first(member) is the name of the member, here
+            // "extremely_cute", or "cute" or "not_so_cute",
+            // and second(member) is its value.
+            return hana::second(member) + total;
+        }) == (5 + 10 + 0)
+    );
+}