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Diffstat (limited to 'src/boost/libs/hana/example/string/foldable.cpp')
-rw-r--r-- | src/boost/libs/hana/example/string/foldable.cpp | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/src/boost/libs/hana/example/string/foldable.cpp b/src/boost/libs/hana/example/string/foldable.cpp new file mode 100644 index 000000000..d1d4661ec --- /dev/null +++ b/src/boost/libs/hana/example/string/foldable.cpp @@ -0,0 +1,26 @@ +// 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/equal.hpp> +#include <boost/hana/fold_left.hpp> +#include <boost/hana/integral_constant.hpp> +#include <boost/hana/plus.hpp> +#include <boost/hana/string.hpp> +#include <boost/hana/value.hpp> +namespace hana = boost::hana; + + +int main() { + auto sum_string = [](auto str) { + return hana::fold_left(str, hana::int_c<0>, [](auto sum, auto c) { + constexpr int i = hana::value(c) - 48; // convert character to decimal + return sum + hana::int_c<i>; + }); + }; + + BOOST_HANA_CONSTANT_CHECK( + sum_string(BOOST_HANA_STRING("1234")) == hana::int_c<1 + 2 + 3 + 4> + ); +} |