support/nonterminal/extract_param.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003     Copyright (c) 2001-2011 Hartmut Kaiser
0004     Copyright (c) 2009 Francois Barel
0005
0006     Distributed under the Boost Software License, Version 1.0. (See accompanying
0007     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0008 ==============================================================================*/
0009 #if !defined(BOOST_SPIRIT_EXTRACT_PARAM_AUGUST_08_2009_0848AM)
0010 #define BOOST_SPIRIT_EXTRACT_PARAM_AUGUST_08_2009_0848AM
0011
0012 #if defined(_MSC_VER)
0013 #pragma once
0014 #endif
0015
0016 #include <boost/spirit/home/support/meta_compiler.hpp>
0017 #include <boost/spirit/home/support/nonterminal/locals.hpp>
0018 #include <boost/spirit/home/support/unused.hpp>
0019 #include <boost/spirit/home/support/common_terminals.hpp>
0020
0021 #include <boost/function_types/is_function.hpp>
0022 #include <boost/function_types/parameter_types.hpp>
0023 #include <boost/function_types/result_type.hpp>
0024 #include <boost/fusion/include/as_list.hpp>
0025 #include <boost/fusion/include/as_vector.hpp>
0026 #include <boost/mpl/deref.hpp>
0027 #include <boost/mpl/end.hpp>
0028 #include <boost/mpl/eval_if.hpp>
0029 #include <boost/mpl/find_if.hpp>
0030 #include <boost/mpl/identity.hpp>
0031 #include <boost/mpl/if.hpp>
0032 #include <boost/mpl/or.hpp>
0033 #include <boost/mpl/and.hpp>
0034 #include <boost/mpl/placeholders.hpp>
0035 #include <boost/type_traits/is_same.hpp>
0036
0037 namespace boost { namespace spirit { namespace detail
0038 {
0039     ///////////////////////////////////////////////////////////////////////////
0040     // Helpers to extract params (locals, attributes, ...) from nonterminal
0041     // template arguments
0042     ///////////////////////////////////////////////////////////////////////////
0043     template <typename Types, typename Pred, typename Default>
0044     struct extract_param
0045     {
0046         typedef typename mpl::find_if<Types, Pred>::type pos;
0047
0048         typedef typename
0049             mpl::eval_if<
0050                 is_same<pos, typename mpl::end<Types>::type>
0051               , mpl::identity<Default>
0052               , mpl::deref<pos>
0053             >::type
0054         type;
0055     };
0056
0057     ///////////////////////////////////////////////////////////////////////////
0058     template <typename Types>
0059     struct extract_locals
0060       : fusion::result_of::as_vector<
0061             typename extract_param<
0062                 Types
0063               , is_locals<mpl::_>
0064               , locals<>
0065             >::type
0066         >
0067     {};
0068
0069     ///////////////////////////////////////////////////////////////////////////
0070     template <typename Domain, typename Types>
0071     struct extract_component
0072       : spirit::result_of::compile<
0073             Domain
0074           , typename extract_param<
0075                 Types
0076               , traits::matches<Domain, mpl::_>
0077               , unused_type
0078             >::type
0079         >
0080     {};
0081
0082     ///////////////////////////////////////////////////////////////////////////
0083     template <typename T>
0084     struct make_function_type : mpl::identity<T()> {};
0085
0086     ///////////////////////////////////////////////////////////////////////////
0087     template <typename Types, typename Encoding, typename Domain>
0088     struct extract_sig
0089     {
0090         typedef typename
0091             extract_param<
0092                 Types
0093               , mpl::or_<
0094                     function_types::is_function<mpl::_>
0095                   , mpl::and_<
0096                         mpl::not_<is_locals<mpl::_> >
0097                       , mpl::not_<is_same<mpl::_, Encoding> >
0098                       , mpl::not_<traits::matches<Domain, mpl::_> >
0099                       , mpl::not_<is_same<mpl::_, unused_type> >
0100                     >
0101                 >
0102               , void()
0103             >::type
0104         attr_of_ftype;
0105
0106         typedef typename
0107             mpl::eval_if<
0108                 function_types::is_function<attr_of_ftype>
0109               , mpl::identity<attr_of_ftype>
0110               , make_function_type<attr_of_ftype>
0111             >::type
0112         type;
0113     };
0114
0115     template <typename Sig>
0116     struct attr_from_sig
0117     {
0118         typedef typename function_types::result_type<Sig>::type attr;
0119
0120         typedef typename
0121             mpl::if_<
0122                 is_same<attr, void>
0123               , unused_type
0124               , attr
0125             >::type
0126         type;
0127     };
0128
0129     template <typename Sig>
0130     struct params_from_sig
0131     {
0132         typedef typename function_types::parameter_types<Sig>::type params;
0133
0134         typedef typename fusion::result_of::as_list<params>::type type;
0135     };
0136
0137     ///////////////////////////////////////////////////////////////////////////
0138     template <typename Types>
0139     struct extract_encoding
0140       : extract_param<
0141             Types
0142           , is_char_encoding<mpl::_>
0143           , unused_type
0144         >
0145     {};
0146 }}}
0147
0148 #endif