137 lines
2.9 KiB
C++
137 lines
2.9 KiB
C++
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// Copyright 2017 Peter Dimov.
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//
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// Distributed under the Boost Software License, Version 1.0.
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//
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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#include <boost/variant2/variant.hpp>
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using namespace boost::variant2;
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struct X
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{
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int v;
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X() = default;
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constexpr explicit X( int v ): v( v ) {}
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constexpr operator int() const { return v; }
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};
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struct Y
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{
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int v;
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constexpr Y(): v() {}
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constexpr explicit Y( int v ): v( v ) {}
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constexpr operator int() const { return v; }
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};
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#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
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template<class V, std::size_t I, class A> constexpr A test( A const& a )
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{
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V v;
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v.template emplace<I>( a );
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return get<I>(v);
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}
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int main()
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{
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{
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constexpr auto w = test<variant<int>, 0>( 1 );
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STATIC_ASSERT( w == 1 );
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}
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{
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constexpr auto w = test<variant<X>, 0>( 1 );
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STATIC_ASSERT( w == 1 );
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}
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#if defined( BOOST_LIBSTDCXX_VERSION ) && BOOST_LIBSTDCXX_VERSION < 50000
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#else
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{
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constexpr auto w = test<variant<Y>, 0>( 1 );
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STATIC_ASSERT( w == 1 );
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}
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#endif
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{
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constexpr auto w = test<variant<int, float>, 0>( 1 );
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STATIC_ASSERT( w == 1 );
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}
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{
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constexpr auto w = test<variant<int, float>, 1>( 3.0f );
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STATIC_ASSERT( w == 3.0f );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, X, X>, 0>( 1 );
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STATIC_ASSERT( w == 1 );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, X, X>, 1>( 1 );
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STATIC_ASSERT( w == 1 );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, X, X>, 2>( 2.0f );
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STATIC_ASSERT( w == 2.0f );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, X, X>, 3>( 3.0f );
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STATIC_ASSERT( w == 3.0f );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, X, X>, 4>( 4 );
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STATIC_ASSERT( w == 4 );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, X, X>, 5>( 5 );
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STATIC_ASSERT( w == 5 );
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}
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#if defined( BOOST_LIBSTDCXX_VERSION ) && BOOST_LIBSTDCXX_VERSION < 50000
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#else
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{
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constexpr auto w = test<variant<int, int, float, float, Y, Y>, 0>( 1 );
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STATIC_ASSERT( w == 1 );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, Y, Y>, 1>( 1 );
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STATIC_ASSERT( w == 1 );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, Y, Y>, 2>( 2.0f );
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STATIC_ASSERT( w == 2.0f );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, Y, Y>, 3>( 3.0f );
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STATIC_ASSERT( w == 3.0f );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, Y, Y>, 4>( 4 );
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STATIC_ASSERT( w == 4 );
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}
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{
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constexpr auto w = test<variant<int, int, float, float, Y, Y>, 5>( 5 );
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STATIC_ASSERT( w == 5 );
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}
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#endif
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}
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