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Diffstat (limited to '')
-rw-r--r-- | src/boost/libs/hana/example/fold.cpp | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/src/boost/libs/hana/example/fold.cpp b/src/boost/libs/hana/example/fold.cpp new file mode 100644 index 000000000..a351be580 --- /dev/null +++ b/src/boost/libs/hana/example/fold.cpp @@ -0,0 +1,38 @@ +// 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/fold.hpp> +#include <boost/hana/tuple.hpp> + +#include <sstream> +#include <string> +namespace hana = boost::hana; + + +auto to_string = [](auto x) { + std::ostringstream ss; + ss << x; + return ss.str(); +}; + +int main() { + auto f = [=](std::string s, auto element) { + return "f(" + s + ", " + to_string(element) + ")"; + }; + + // with an initial state + BOOST_HANA_RUNTIME_CHECK( + hana::fold(hana::make_tuple(2, '3', 4, 5.0), "1", f) + == + "f(f(f(f(1, 2), 3), 4), 5)" + ); + + // without initial state + BOOST_HANA_RUNTIME_CHECK( + hana::fold(hana::make_tuple("1", 2, '3', 4, 5.0), f) + == + "f(f(f(f(1, 2), 3), 4), 5)" + ); +} |