| 1 | /* |
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| 2 | Copyright 2020 Glen Joseph Fernandes |
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| 3 | (glenjofe@gmail.com) |
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| 4 | |
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| 5 | Distributed under the Boost Software License, |
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| 6 | Version 1.0. (See accompanying file LICENSE_1_0.txt |
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| 7 | or copy at http://www.boost.org/LICENSE_1_0.txt) |
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| 8 | */ |
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| 9 | |
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| 10 | #ifndef BOOST_TT_DISJUNCTION_HPP_INCLUDED |
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| 11 | #define BOOST_TT_DISJUNCTION_HPP_INCLUDED |
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| 12 | |
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| 13 | #include <boost/type_traits/conditional.hpp> |
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| 14 | #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) |
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| 15 | #include <boost/type_traits/integral_constant.hpp> |
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| 16 | #endif |
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| 17 | |
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| 18 | namespace boost { |
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| 19 | |
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| 20 | #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) |
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| 21 | template<class...> |
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| 22 | struct disjunction |
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| 23 | : false_type { }; |
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| 24 | |
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| 25 | template<class T> |
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| 26 | struct disjunction<T> |
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| 27 | : T { }; |
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| 28 | |
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| 29 | template<class T, class... U> |
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| 30 | struct disjunction<T, U...> |
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| 31 | : conditional<bool(T::value), T, disjunction<U...> >::type { }; |
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| 32 | #else |
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| 33 | template<class T, class U> |
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| 34 | struct disjunction |
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| 35 | : conditional<bool(T::value), T, U>::type { }; |
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| 36 | #endif |
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| 37 | |
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| 38 | } /* boost */ |
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| 39 | |
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| 40 | #endif |
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| 41 | |
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