1 ///////////////////////////////////////////////////////////////////////////////
2 /// \file pack.hpp
3 /// Contains helpers for pseudo-pack expansion.
4 //
5 //  Copyright 2012 Eric Niebler. Distributed under the Boost
6 //  Software License, Version 1.0. (See accompanying file
7 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
8 
9 #ifndef BOOST_PROTO_TRANSFORM_DETAIL_PACK_HPP_EAN_2012_07_11
10 #define BOOST_PROTO_TRANSFORM_DETAIL_PACK_HPP_EAN_2012_07_11
11 
12 #include <boost/preprocessor/cat.hpp>
13 #include <boost/preprocessor/arithmetic/inc.hpp>
14 #include <boost/preprocessor/arithmetic/dec.hpp>
15 #include <boost/preprocessor/arithmetic/sub.hpp>
16 #include <boost/preprocessor/punctuation/comma_if.hpp>
17 #include <boost/preprocessor/repetition/enum.hpp>
18 #include <boost/preprocessor/repetition/enum_params.hpp>
19 #include <boost/preprocessor/repetition/enum_trailing_params.hpp>
20 #include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
21 #include <boost/preprocessor/repetition/repeat.hpp>
22 #include <boost/preprocessor/iteration/local.hpp>
23 #include <boost/preprocessor/iteration/iterate.hpp>
24 #include <boost/mpl/bool.hpp>
25 #include <boost/mpl/assert.hpp>
26 #include <boost/type_traits/is_same.hpp>
27 #include <boost/proto/proto_fwd.hpp>
28 
29 #if defined(_MSC_VER)
30 # pragma warning(push)
31 # pragma warning(disable: 4348) // redefinition of default parameter
32 #endif
33 
34 namespace boost { namespace proto
35 {
36     namespace detail
37     {
38         template<typename Fun>
39         struct msvc_fun_workaround;
40 
41         template<typename Tfx, typename T>
42         struct expand_pattern_helper
43         {
44             typedef T type;
45             typedef mpl::false_ applied;
46         };
47 
48         template<typename Tfx, typename Fun>
49         struct expand_pattern_helper<Tfx, Fun *>
50           : expand_pattern_helper<Tfx, Fun>
51         {};
52 
53         template<typename Tfx, typename T>
54         struct expand_pattern_helper<Tfx, pack(T)>
55         {
56             // BUGBUG fix me. See comment in transform/detail/call.hpp
57             BOOST_MPL_ASSERT_MSG(
58                 (is_same<T, _>::value)
59               , PACK_EXPANSIONS_OF_EXPRESSIONS_OTHER_THAN_THE_CURRENT_NOT_YET_SUPPORTED
60               , (T)
61             );
62             typedef Tfx type(T);
63             typedef mpl::true_ applied;
64         };
65 
66         template<typename Tfx>
67         struct expand_pattern_helper<Tfx, pack(_)>
68         {
69             typedef Tfx type;
70             typedef mpl::true_ applied;
71         };
72 
73         #include <boost/proto/transform/detail/expand_pack.hpp>
74 
75         template<long Arity, typename Fun, typename Cont>
76         struct expand_pattern;
77 
78         template<typename Fun, typename Cont>
79         struct expand_pattern<0, Fun, Cont>
80           : Cont::template cat<typename expand_pattern_helper<proto::_value, Fun>::type>
81         {
82             BOOST_MPL_ASSERT_MSG(
83                 (expand_pattern_helper<proto::_value, Fun>::applied::value)
84               , NO_PACK_EXPRESSION_FOUND_IN_PACK_EXPANSION
85               , (Fun)
86             );
87         };
88 
89         #include <boost/proto/transform/detail/pack_impl.hpp>
90     }
91 }}
92 
93 #if defined(_MSC_VER)
94 # pragma warning(pop)
95 #endif
96 
97 #endif
98