// Copyright (c) 2001-2011 Hartmut Kaiser
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#if !defined(BOOST_SPIRIT_SUPPORT_META_CREATE_NOV_21_2009_0327PM)
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#define BOOST_SPIRIT_SUPPORT_META_CREATE_NOV_21_2009_0327PM
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#if defined(_MSC_VER)
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#pragma once
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#endif
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#include <boost/spirit/home/support/unused.hpp>
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#include <boost/version.hpp>
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#include <boost/proto/make_expr.hpp>
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#include <boost/proto/traits.hpp>
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#include <boost/utility/result_of.hpp>
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#include <boost/type_traits/add_const.hpp>
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#include <boost/type_traits/add_reference.hpp>
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#include <boost/type_traits/remove_const.hpp>
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#include <boost/type_traits/remove_reference.hpp>
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#include <boost/fusion/include/fold.hpp>
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#include <boost/mpl/and.hpp>
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#include <boost/mpl/not.hpp>
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// needed for workaround below
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#if defined(__GNUC__) && ((__GNUC__ < 4) || (__GNUC__ == 4) && (__GNUC_MINOR__ < 3))
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#include <boost/type_traits/is_same.hpp>
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#endif
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namespace boost { namespace spirit { namespace traits
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{
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///////////////////////////////////////////////////////////////////////////
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// This is the main dispatch point for meta_create to the correct domain
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template <typename Domain, typename T, typename Enable = void>
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struct meta_create;
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///////////////////////////////////////////////////////////////////////////
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// This allows to query whether a valid mapping exists for the given data
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// type to a component in the given domain
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template <typename Domain, typename T, typename Enable = void>
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struct meta_create_exists : mpl::false_ {};
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}}}
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namespace boost { namespace spirit
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{
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///////////////////////////////////////////////////////////////////////////
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namespace detail
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{
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template <typename T>
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struct add_const_ref
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: add_reference<typename add_const<T>::type> {};
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template <typename T>
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struct remove_const_ref
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: remove_const<typename remove_reference<T>::type> {};
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// starting with Boost V1.42 fusion::fold has been changed to be compatible
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// with mpl::fold (the sequence of template parameters for the meta-function
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// object has been changed)
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#if BOOST_VERSION < 104200
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///////////////////////////////////////////////////////////////////////
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template <typename OpTag, typename Domain>
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struct nary_proto_expr_function
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{
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template <typename T>
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struct result;
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// this is a workaround for older versions of g++ (< V4.3) which apparently have
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// problems with the following template specialization
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#if defined(__GNUC__) && ((__GNUC__ < 4) || (__GNUC__ == 4) && (__GNUC_MINOR__ < 3))
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template <typename F, typename T1, typename T2>
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struct result<F(T1, T2)>
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{
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BOOST_STATIC_ASSERT((is_same<F, nary_proto_expr_function>::value));
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#else
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template <typename T1, typename T2>
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struct result<nary_proto_expr_function(T1, T2)>
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{
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#endif
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typedef typename remove_const_ref<T2>::type left_type;
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typedef typename
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spirit::traits::meta_create<Domain, T1>::type
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right_type;
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typedef typename mpl::eval_if<
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traits::not_is_unused<left_type>
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, proto::result_of::make_expr<OpTag, left_type, right_type>
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, mpl::identity<right_type>
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>::type type;
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};
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template <typename T>
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typename result<nary_proto_expr_function(T, unused_type const&)>::type
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operator()(T, unused_type const&) const
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{
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typedef spirit::traits::meta_create<Domain, T> right_type;
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return right_type::call();
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}
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template <typename T1, typename T2>
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typename result<nary_proto_expr_function(T1, T2)>::type
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operator()(T1, T2 const& t2) const
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{
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// we variants to the alternative operator
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typedef spirit::traits::meta_create<Domain, T1> right_type;
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return proto::make_expr<OpTag>(t2, right_type::call());
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}
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};
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#else
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///////////////////////////////////////////////////////////////////////
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template <typename OpTag, typename Domain>
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struct nary_proto_expr_function
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{
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template <typename T>
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struct result;
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// this is a workaround for older versions of g++ (< V4.3) which apparently have
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// problems with the following template specialization
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#if defined(__GNUC__) && ((__GNUC__ < 4) || (__GNUC__ == 4) && (__GNUC_MINOR__ < 3))
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template <typename F, typename T1, typename T2>
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struct result<F(T1, T2)>
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{
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BOOST_STATIC_ASSERT((is_same<F, nary_proto_expr_function>::value));
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#else
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template <typename T1, typename T2>
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struct result<nary_proto_expr_function(T1, T2)>
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{
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#endif
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typedef typename remove_const_ref<T1>::type left_type;
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typedef typename
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spirit::traits::meta_create<Domain, T2>::type
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right_type;
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typedef typename mpl::eval_if<
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traits::not_is_unused<left_type>
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, proto::result_of::make_expr<OpTag, left_type, right_type>
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, mpl::identity<right_type>
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>::type type;
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};
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template <typename T>
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typename result<nary_proto_expr_function(unused_type const&, T)>::type
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operator()(unused_type const&, T) const
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{
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typedef spirit::traits::meta_create<Domain, T> right_type;
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return right_type::call();
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}
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template <typename T1, typename T2>
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typename result<nary_proto_expr_function(T1, T2)>::type
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operator()(T1 const& t1, T2) const
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{
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// we variants to the alternative operator
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typedef spirit::traits::meta_create<Domain, T2> right_type;
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return proto::make_expr<OpTag>(t1, right_type::call());
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}
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};
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#endif
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}
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///////////////////////////////////////////////////////////////////////
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template <typename T, typename OpTag, typename Domain>
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struct make_unary_proto_expr
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{
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typedef spirit::traits::meta_create<Domain, T> subject_type;
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typedef typename proto::result_of::make_expr<
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OpTag, typename subject_type::type
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>::type type;
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static type call()
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{
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return proto::make_expr<OpTag>(subject_type::call());
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}
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};
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///////////////////////////////////////////////////////////////////////////
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template <typename Sequence, typename OpTag, typename Domain>
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struct make_nary_proto_expr
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{
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typedef detail::nary_proto_expr_function<OpTag, Domain>
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make_proto_expr;
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typedef typename fusion::result_of::fold<
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Sequence, unused_type, make_proto_expr
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>::type type;
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static type call()
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{
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return fusion::fold(Sequence(), unused, make_proto_expr());
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}
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};
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///////////////////////////////////////////////////////////////////////////
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namespace detail
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{
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// Starting with newer versions of Proto, all Proto expressions are at
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// the same time Fusion sequences. This is the correct behavior, but
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// we need to distinguish between Fusion sequences and Proto
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// expressions. This meta-function does exactly that.
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template <typename T>
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struct is_fusion_sequence_but_not_proto_expr
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: mpl::and_<
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fusion::traits::is_sequence<T>
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, mpl::not_<proto::is_expr<T> > >
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{};
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}
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}}
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#endif
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