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| 2 | #ifndef BOOST_MPL_AUX_PUSH_FRONT_IMPL_HPP_INCLUDED |
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| 3 | #define BOOST_MPL_AUX_PUSH_FRONT_IMPL_HPP_INCLUDED |
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| 4 | |
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| 5 | // Copyright Aleksey Gurtovoy 2000-2008 |
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| 6 | // |
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| 7 | // Distributed under the Boost Software License, Version 1.0. |
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| 8 | // (See accompanying file LICENSE_1_0.txt or copy at |
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| 9 | // http://www.boost.org/LICENSE_1_0.txt) |
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| 10 | // |
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| 11 | // See http://www.boost.org/libs/mpl for documentation. |
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| 12 | |
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| 13 | // $Id$ |
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| 14 | // $Date$ |
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| 15 | // $Revision$ |
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| 16 | |
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| 17 | #include <boost/mpl/push_front_fwd.hpp> |
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| 18 | #include <boost/mpl/assert.hpp> |
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| 19 | #include <boost/mpl/aux_/has_type.hpp> |
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| 20 | #include <boost/mpl/aux_/traits_lambda_spec.hpp> |
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| 21 | #include <boost/mpl/aux_/config/forwarding.hpp> |
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| 22 | #include <boost/mpl/aux_/config/static_constant.hpp> |
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| 23 | |
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| 24 | #include <boost/type_traits/is_same.hpp> |
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| 25 | |
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| 26 | namespace boost { namespace mpl { |
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| 27 | |
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| 28 | struct has_push_front_arg {}; |
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| 29 | |
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| 30 | // agurt 05/feb/04: no default implementation; the stub definition is needed |
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| 31 | // to enable the default 'has_push_front' implementation below |
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| 32 | |
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| 33 | template< typename Tag > |
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| 34 | struct push_front_impl |
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| 35 | { |
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| 36 | template< typename Sequence, typename T > struct apply |
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| 37 | { |
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| 38 | // should be instantiated only in the context of 'has_push_front_impl'; |
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| 39 | // if you've got an assert here, you are requesting a 'push_front' |
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| 40 | // specialization that doesn't exist. |
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| 41 | BOOST_MPL_ASSERT_MSG( |
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| 42 | ( boost::is_same< T, has_push_front_arg >::value ) |
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| 43 | , REQUESTED_PUSH_FRONT_SPECIALIZATION_FOR_SEQUENCE_DOES_NOT_EXIST |
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| 44 | , ( Sequence ) |
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| 45 | ); |
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| 46 | }; |
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| 47 | }; |
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| 48 | |
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| 49 | template< typename Tag > |
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| 50 | struct has_push_front_impl |
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| 51 | { |
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| 52 | template< typename Seq > struct apply |
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| 53 | #if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING) |
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| 54 | : aux::has_type< push_front< Seq, has_push_front_arg > > |
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| 55 | { |
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| 56 | #else |
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| 57 | { |
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| 58 | typedef aux::has_type< push_front< Seq, has_push_front_arg > > type; |
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| 59 | BOOST_STATIC_CONSTANT(bool, value = |
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| 60 | (aux::has_type< push_front< Seq, has_push_front_arg > >::value) |
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| 61 | ); |
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| 62 | #endif |
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| 63 | }; |
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| 64 | }; |
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| 65 | |
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| 66 | BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(2, push_front_impl) |
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| 67 | BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(1, has_push_front_impl) |
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| 68 | |
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| 69 | }} |
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| 70 | |
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| 71 | #endif // BOOST_MPL_AUX_PUSH_FRONT_IMPL_HPP_INCLUDED |
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| 72 | |
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