libstdc++-v3/testsuite/experimental/optional/constexpr/relops/5.cc

   1 // { dg-do compile { target c++14 } }
   2
   3 // Copyright (C) 2013-2017 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20 #include <experimental/optional>
  21 #include <testsuite_hooks.h>
  22
  23 namespace ns
  24 {
  25   struct value_type
  26   {
  27     int i;
  28     const char* s;
  29   };
  30
  31   constexpr bool
  32   strcmp(const char* lhs, const char* rhs)
  33   {
  34     return *lhs == *rhs && (!*lhs || strcmp(lhs + 1, rhs + 1));
  35   }
  36
  37   constexpr bool
  38   strrel(const char* lhs, const char* rhs)
  39   {
  40     return (*rhs && (!*lhs || (*lhs < *rhs)))
  41       || ((*lhs && *rhs && !(*rhs < *lhs)) && strrel(lhs + 1, rhs + 1));
  42   }
  43
  44   constexpr bool
  45   operator==(value_type const& lhs, value_type const& rhs)
  46   { return (lhs.i == rhs.i) && strcmp(lhs.s, rhs.s); }
  47
  48   constexpr bool
  49   operator!=(value_type const& lhs, value_type const& rhs)
  50   { return !(lhs == rhs); }
  51
  52   constexpr bool
  53   operator<(value_type const& lhs, value_type const& rhs)
  54   { return (lhs.i < rhs.i) || (!(rhs.i < lhs.i) && strrel(lhs.s, rhs.s)); }
  55
  56 } // namespace ns
  57
  58 int main()
  59 {
  60   using ns::value_type;
  61   using O = std::experimental::optional<value_type>;
  62   using std::experimental::nullopt;
  63
  64   {
  65     constexpr O o;
  66     static_assert( o == nullopt, "" );
  67     static_assert( nullopt == o, "" );
  68     static_assert( !(o != nullopt), "" );
  69     static_assert( !(nullopt != o), "" );
  70   }
  71
  72   {
  73     constexpr O o { std::experimental::in_place };
  74     static_assert( !(o == nullopt), "" );
  75     static_assert( !(nullopt == o), "" );
  76     static_assert( o != nullopt, "" );
  77     static_assert( nullopt != o, "" );
  78   }
  79 }