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1 | /*============================================================================= | |
2 | Copyright (c) 2001-2011 Joel de Guzman | |
3 | Copyright (c) 2006 Dan Marsden | |
4 | ||
5 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
6 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
7 | ==============================================================================*/ | |
8 | #if !defined(FUSION_VALUE_OF_IMPL_20060124_2147) | |
9 | #define FUSION_VALUE_OF_IMPL_20060124_2147 | |
10 | ||
11 | #include <boost/fusion/support/config.hpp> | |
12 | #include <boost/fusion/container/vector/convert.hpp> | |
13 | #include <boost/fusion/algorithm/transformation/transform.hpp> | |
14 | #include <boost/fusion/iterator/value_of.hpp> | |
15 | #include <boost/mpl/placeholders.hpp> | |
16 | #include <boost/fusion/support/unused.hpp> | |
17 | #include <boost/mpl/eval_if.hpp> | |
18 | #include <boost/mpl/identity.hpp> | |
19 | #include <boost/type_traits/is_same.hpp> | |
20 | #include <boost/config.hpp> | |
21 | ||
22 | namespace boost { namespace fusion | |
23 | { | |
24 | struct zip_view_iterator_tag; | |
25 | ||
26 | namespace detail | |
27 | { | |
28 | struct poly_value_of | |
29 | { | |
30 | template<typename T> | |
31 | struct result; | |
32 | ||
33 | template<typename It> | |
34 | struct result<poly_value_of(It)> | |
35 | : mpl::eval_if<is_same<It, unused_type>, | |
36 | mpl::identity<unused_type>, | |
37 | result_of::value_of<It> > | |
38 | {}; | |
39 | ||
40 | // never called, but needed for decltype-based result_of (C++0x) | |
41 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
42 | template<typename It> | |
43 | BOOST_FUSION_GPU_ENABLED | |
44 | typename result<poly_value_of(It)>::type | |
45 | operator()(It&&) const; | |
46 | #endif | |
47 | }; | |
48 | } | |
49 | ||
50 | namespace extension | |
51 | { | |
52 | template<typename Tag> | |
53 | struct value_of_impl; | |
54 | ||
55 | template<> | |
56 | struct value_of_impl<zip_view_iterator_tag> | |
57 | { | |
58 | template<typename Iterator> | |
59 | struct apply | |
60 | { | |
61 | typedef typename result_of::transform< | |
62 | typename Iterator::iterators, | |
63 | detail::poly_value_of>::type values; | |
64 | ||
65 | typedef typename result_of::as_vector<values>::type type; | |
66 | }; | |
67 | }; | |
68 | } | |
69 | }} | |
70 | ||
71 | #endif |