| 1 | /*============================================================================= |
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| 2 | Copyright (c) 2001-2014 Joel de Guzman |
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| 3 | http://spirit.sourceforge.net/ |
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| 4 | |
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| 5 | Distributed under the Boost Software License, Version 1.0. (See accompanying |
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| 6 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
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| 7 | =============================================================================*/ |
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| 8 | #if !defined(BOOST_SPIRIT_X3_IS_VARIANT_JAN_10_2012_0823AM) |
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| 9 | #define BOOST_SPIRIT_X3_IS_VARIANT_JAN_10_2012_0823AM |
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| 10 | |
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| 11 | #include <boost/variant.hpp> |
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| 12 | #include <boost/mpl/has_xxx.hpp> |
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| 13 | #include <boost/mpl/bool.hpp> |
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| 14 | |
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| 15 | namespace boost { namespace spirit { namespace x3 { namespace traits |
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| 16 | { |
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| 17 | namespace detail |
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| 18 | { |
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| 19 | // By declaring a nested struct in your class/struct, you tell |
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| 20 | // spirit that it is regarded as a variant type. The minimum |
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| 21 | // required interface for such a variant is that it has constructors |
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| 22 | // for various types supported by your variant and a typedef 'types' |
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| 23 | // which is an mpl sequence of the contained types. |
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| 24 | // |
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| 25 | // This is an intrusive interface. For a non-intrusive interface, |
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| 26 | // use the is_variant trait. |
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| 27 | BOOST_MPL_HAS_XXX_TRAIT_DEF(adapted_variant_tag) |
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| 28 | } |
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| 29 | |
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| 30 | template <typename T, typename Enable = void> |
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| 31 | struct is_variant |
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| 32 | : detail::has_adapted_variant_tag<T> |
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| 33 | {}; |
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| 34 | |
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| 35 | template <BOOST_VARIANT_ENUM_PARAMS(typename T)> |
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| 36 | struct is_variant<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>> |
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| 37 | : mpl::true_ |
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| 38 | {}; |
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| 39 | }}}} |
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| 40 | |
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| 41 | #endif |
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| 42 | |
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