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31 lines
865 B
C++
31 lines
865 B
C++
/*
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@copyright Louis Dionne 2014
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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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*/
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#include <boost/hana/functional.hpp>
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#include <boost/hana/integral.hpp>
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#include <boost/hana/logical.hpp>
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#include <boost/hana/range.hpp>
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#include <cassert>
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#include <sstream>
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using namespace boost::hana;
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using namespace literals;
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int main() {
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//! [main]
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auto to_string = [](auto x) { return (std::ostringstream{} << x).str(); };
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auto show = [=](auto x, auto y) {
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auto y_ = if_(x() < 4_c, y, always("..."))();
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return "(" + to_string(x()) + " + " + to_string(y_) + ")";
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};
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auto state = [] { assert(false); }; // this will never be evaluated
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assert(lazy_foldr(show, state, range(1_c, 999999_c)) == "(1 + (2 + (3 + (4 + ...))))");
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//! [main]
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}
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