ceph/src/boost/libs/yap/example/minimal.cpp

   1 // Copyright (C) 2016-2018 T. Zachary Laine
   2 //
   3 // Distributed under the Boost Software License, Version 1.0. (See
   4 // accompanying file LICENSE_1_0.txt or copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6 #include <boost/yap/algorithm.hpp>
   7
   8 #include <array>
   9 #include <iostream>
  10
  11
  12 //[ minimal_template
  13 template <boost::yap::expr_kind Kind, typename Tuple>
  14 struct minimal_expr
  15 {
  16     static const boost::yap::expr_kind kind = Kind;
  17
  18     Tuple elements;
  19 };
  20 //]
  21
  22
  23 int main()
  24 {
  25 //[ minimal_template_manual_construction
  26     auto left = boost::yap::make_terminal<minimal_expr>(1);
  27     auto right = boost::yap::make_terminal<minimal_expr>(41);
  28
  29     auto expr = boost::yap::make_expression<
  30         minimal_expr,
  31         boost::yap::expr_kind::plus
  32     >(left, right);
  33 //]
  34
  35 //[ minimal_template_evaluation
  36     auto result = boost::yap::evaluate(expr);
  37
  38     std::cout << result << "\n"; // prints "42"
  39 //]
  40
  41     return 0;
  42 }