feat():initial version

install/boost_1_75_0/include/boost/histogram/sample.hpp

@@ -0,0 +1,39 @@
+// Copyright 2019 Hans Dembinski
+//
+// 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)
+
+#ifndef BOOST_HISTOGRAM_SAMPLE_HPP
+#define BOOST_HISTOGRAM_SAMPLE_HPP
+
+#include <tuple>
+#include <utility>
+
+namespace boost {
+namespace histogram {
+
+/** Sample holder and type envelope.
+
+  You should not construct these directly, use the sample() helper function.
+
+  @tparam Underlying type.
+*/
+template <class T>
+struct sample_type {
+  T value;
+};
+
+/** Helper function to mark arguments as sample.
+
+  @param ts arguments to be forwarded to the accumulator.
+*/
+template <class... Ts>
+auto sample(Ts&&... ts) noexcept {
+  return sample_type<std::tuple<Ts...>>{std::forward_as_tuple(std::forward<Ts>(ts)...)};
+}
+
+} // namespace histogram
+} // namespace boost
+
+#endif