ceph/src/boost/libs/hana/test/concept/struct/fold_left.cpp

   1 // Copyright Louis Dionne 2013-2017
   2 // Distributed under the Boost Software License, Version 1.0.
   3 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   4
   5 #include <boost/hana/assert.hpp>
   6 #include <boost/hana/concept/struct.hpp>
   7 #include <boost/hana/equal.hpp>
   8 #include <boost/hana/fold_left.hpp>
   9 #include <boost/hana/integral_constant.hpp>
  10
  11 #include "minimal_struct.hpp"
  12 #include <laws/base.hpp>
  13 #include <support/minimal_product.hpp>
  14 namespace hana = boost::hana;
  15 using hana::test::ct_eq;
  16
  17
  18 template <int i = 0>
  19 struct undefined { };
  20
  21 struct MoveOnly {
  22     MoveOnly()                           = default;
  23     MoveOnly(MoveOnly&&)                 = default;
  24     MoveOnly(MoveOnly const&)            = delete;
  25     MoveOnly& operator=(MoveOnly&&)      = default;
  26     MoveOnly& operator=(MoveOnly const&) = delete;
  27 };
  28
  29 int main() {
  30     constexpr auto pair = ::minimal_product;
  31     ct_eq<999> s{};
  32     hana::test::_injection<0> f{};
  33
  34     BOOST_HANA_CONSTANT_CHECK(hana::equal(
  35         hana::fold_left(obj(), s, undefined<>{}),
  36         s
  37     ));
  38
  39     BOOST_HANA_CONSTANT_CHECK(hana::equal(
  40         hana::fold_left(obj(ct_eq<0>{}), s, f),
  41         f(s, pair(hana::int_c<0>, ct_eq<0>{}))
  42     ));
  43
  44     BOOST_HANA_CONSTANT_CHECK(hana::equal(
  45         hana::fold_left(obj(ct_eq<0>{}, ct_eq<1>{}), s, f),
  46         f(f(s, pair(hana::int_c<0>, ct_eq<0>{})), pair(hana::int_c<1>, ct_eq<1>{}))
  47     ));
  48
  49     BOOST_HANA_CONSTANT_CHECK(hana::equal(
  50         hana::fold_left(obj(ct_eq<0>{}, ct_eq<1>{}, ct_eq<2>{}), s, f),
  51         f(f(f(s, pair(hana::int_c<0>, ct_eq<0>{})),
  52                  pair(hana::int_c<1>, ct_eq<1>{})),
  53                  pair(hana::int_c<2>, ct_eq<2>{}))
  54     ));
  55
  56     // fold_left with move-only members
  57     hana::fold_left(obj(MoveOnly{}), 0, [](int, auto) { return 0; });
  58     hana::fold_left(obj(MoveOnly{}, MoveOnly{}), 0, [](int, auto) { return 0; });
  59 }