27 lines
839 B
C++
27 lines
839 B
C++
// Copyright Louis Dionne 2013-2017
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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#include <boost/hana/assert.hpp>
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#include <boost/hana/equal.hpp>
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#include <boost/hana/fold_left.hpp>
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#include <boost/hana/integral_constant.hpp>
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#include <boost/hana/plus.hpp>
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#include <boost/hana/string.hpp>
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#include <boost/hana/value.hpp>
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namespace hana = boost::hana;
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int main() {
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auto sum_string = [](auto str) {
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return hana::fold_left(str, hana::int_c<0>, [](auto sum, auto c) {
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constexpr int i = hana::value(c) - 48; // convert character to decimal
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return sum + hana::int_c<i>;
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});
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};
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BOOST_HANA_CONSTANT_CHECK(
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sum_string(BOOST_HANA_STRING("1234")) == hana::int_c<1 + 2 + 3 + 4>
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);
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}
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