ceph/src/boost/libs/hana/test/tuple/special.fold_left.cpp

   1 // Copyright Louis Dionne 2013-2016
   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/equal.hpp>
   7 #include <boost/hana/fold_left.hpp>
   8 #include <boost/hana/tuple.hpp>
   9 #include <boost/hana/type.hpp>
  10 namespace hana = boost::hana;
  11
  12
  13 template <typename ...>
  14 struct F { struct type; };
  15
  16 struct x0;
  17 struct x1;
  18 struct x2;
  19 struct x3;
  20
  21 int main() {
  22     // tuple_t and initial state
  23     {
  24         auto f = hana::metafunction<F>;
  25         auto s = hana::type_c<struct initial_state>;
  26         BOOST_HANA_CONSTANT_CHECK(hana::equal(
  27             hana::fold_left(hana::tuple_t<>, s, f),
  28             s
  29         ));
  30         BOOST_HANA_CONSTANT_CHECK(hana::equal(
  31             hana::fold_left(hana::tuple_t<x0>, s, f),
  32             f(s, hana::type_c<x0>)
  33         ));
  34         BOOST_HANA_CONSTANT_CHECK(hana::equal(
  35             hana::fold_left(hana::tuple_t<x0, x1>, s, f),
  36             f(f(s, hana::type_c<x0>), hana::type_c<x1>)
  37         ));
  38         BOOST_HANA_CONSTANT_CHECK(hana::equal(
  39             hana::fold_left(hana::tuple_t<x0, x1, x2>, s, f),
  40             f(f(f(s, hana::type_c<x0>), hana::type_c<x1>), hana::type_c<x2>)
  41         ));
  42         BOOST_HANA_CONSTANT_CHECK(hana::equal(
  43             hana::fold_left(hana::tuple_t<x0, x1, x2, x3>, s, f),
  44             f(f(f(f(s, hana::type_c<x0>), hana::type_c<x1>), hana::type_c<x2>), hana::type_c<x3>)
  45         ));
  46     }
  47
  48     // tuple_t and no initial state
  49     {
  50         auto f = hana::metafunction<F>;
  51         BOOST_HANA_CONSTANT_CHECK(hana::equal(
  52             hana::fold_left(hana::tuple_t<x0>, f),
  53             hana::type_c<x0>
  54         ));
  55         BOOST_HANA_CONSTANT_CHECK(hana::equal(
  56             hana::fold_left(hana::tuple_t<x0, x1>, f),
  57             f(hana::type_c<x0>, hana::type_c<x1>)
  58         ));
  59         BOOST_HANA_CONSTANT_CHECK(hana::equal(
  60             hana::fold_left(hana::tuple_t<x0, x1, x2>, f),
  61             f(f(hana::type_c<x0>, hana::type_c<x1>), hana::type_c<x2>)
  62         ));
  63         BOOST_HANA_CONSTANT_CHECK(hana::equal(
  64             hana::fold_left(hana::tuple_t<x0, x1, x2, x3>, f),
  65             f(f(f(hana::type_c<x0>, hana::type_c<x1>), hana::type_c<x2>), hana::type_c<x3>)
  66         ));
  67     }
  68 }