1 ///////////////////////////////////////////////////////////////////////////////
2 /// \file template_arity.hpp
3 /// Replace all nodes stored by reference by nodes stored by value.
4 //
5 //  Copyright 2011 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 //  This file is based on a similar one in MPL from Aleksey Gurtovoy.
10 
11 #ifndef BOOST_PROTO_DETAIL_TEMPLATE_ARITY_HPP_EAN_2011_05_07
12 #define BOOST_PROTO_DETAIL_TEMPLATE_ARITY_HPP_EAN_2011_05_07
13 
14 // Somewhat indirect definition of BOOST_PROTO_TEMPLATE_ARITY_PARAM is
15 // to overcome a shortcoming of the Wave tool used to generate the
16 // pre-preprocessed headers.
17 #define BOOST_PROTO_TEMPLATE_ARITY_PARAM BOOST_PROTO_TEMPLATE_ARITY_PARAM2
18 #define BOOST_PROTO_TEMPLATE_ARITY_PARAM2(param)
19 
20 #if defined(BOOST_PROTO_EXTENDED_TEMPLATE_PARAMETERS_MATCHING) ||                                   \
21   (defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES))
22 
23 #include <boost/preprocessor/cat.hpp>
24 #include <boost/preprocessor/inc.hpp>
25 #include <boost/preprocessor/iteration/iterate.hpp>
26 #include <boost/preprocessor/repetition/enum_params.hpp>
27 #include <boost/mpl/int.hpp>
28 #include <boost/proto/proto_fwd.hpp>
29 
30 #undef BOOST_PROTO_TEMPLATE_ARITY_PARAM2
31 #define BOOST_PROTO_TEMPLATE_ARITY_PARAM2(param) , param
32 
33 namespace boost { namespace proto { namespace detail
34 {
35     sized_type<1>::type template_arity_helper(...);
36 
37     // Other overloads generated by the preprocessor
38     #include <boost/proto/detail/template_arity_helper.hpp>
39 
40     template<typename F, int N, int Size>
41     struct template_arity_impl2
42       : mpl::int_<Size - 1>
43     {};
44 
45     template<typename F, int N = BOOST_PROTO_MAX_ARITY>
46     struct template_arity
47       : template_arity_impl2<
48             F
49           , N
50           , sizeof(detail::template_arity_helper((F **)0, (mpl::int_<N> *)0))
51         >
52     {};
53 
54     template<typename F, int N>
55     struct template_arity_impl2<F, N, 1>
56       : template_arity<F, N-1>
57     {};
58 
59     template<typename F>
60     struct template_arity_impl2<F, 0, 1>
61       : mpl::int_<-1>
62     {};
63 
64 }}}
65 
66 #endif // BOOST_PROTO_EXTENDED_TEMPLATE_PARAMETERS_MATCHING
67 #endif // BOOST_PROTO_DETAIL_TEMPLATE_ARITY_HPP_EAN_2011_05_07
68