| /////////////////////////////////////////////////////////////////////////////// |
| /// \file as_expr.hpp |
| /// Contains definition of the as_expr\<\> and as_child\<\> helper class |
| /// templates used to implement proto::domain's as_expr\<\> and as_child\<\> |
| /// member templates. |
| // |
| // Copyright 2010 Eric Niebler. Distributed under the Boost |
| // Software License, Version 1.0. (See accompanying file |
| // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| |
| #ifndef BOOST_PROTO_DETAIL_AS_EXPR_HPP_EAN_06_09_2010 |
| #define BOOST_PROTO_DETAIL_AS_EXPR_HPP_EAN_06_09_2010 |
| |
| #include <boost/config.hpp> |
| #include <boost/detail/workaround.hpp> |
| #include <boost/type_traits/remove_const.hpp> |
| #include <boost/proto/proto_fwd.hpp> |
| #include <boost/proto/args.hpp> |
| |
| namespace boost { namespace proto { namespace detail |
| { |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename Generator> |
| struct base_generator |
| { |
| typedef Generator type; |
| }; |
| |
| template<typename Generator> |
| struct base_generator<use_basic_expr<Generator> > |
| { |
| typedef Generator type; |
| }; |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename T, typename Generator, bool WantsBasicExpr> |
| struct as_expr; |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename T, typename Generator> |
| struct as_expr<T, Generator, false> |
| { |
| typedef typename term_traits<T &>::value_type value_type; |
| typedef proto::expr<proto::tag::terminal, term<value_type>, 0> expr_type; |
| typedef typename Generator::template result<Generator(expr_type)>::type result_type; |
| |
| result_type operator()(T &t) const |
| { |
| return Generator()(expr_type::make(t)); |
| } |
| }; |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename T, typename Generator> |
| struct as_expr<T, Generator, true> |
| { |
| typedef typename term_traits<T &>::value_type value_type; |
| typedef proto::basic_expr<proto::tag::terminal, term<value_type>, 0> expr_type; |
| typedef typename Generator::template result<Generator(expr_type)>::type result_type; |
| |
| result_type operator()(T &t) const |
| { |
| return Generator()(expr_type::make(t)); |
| } |
| }; |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename T> |
| struct as_expr<T, proto::default_generator, false> |
| { |
| typedef typename term_traits<T &>::value_type value_type; |
| typedef proto::expr<proto::tag::terminal, term<value_type>, 0> result_type; |
| |
| result_type operator()(T &t) const |
| { |
| return result_type::make(t); |
| } |
| }; |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename T> |
| struct as_expr<T, proto::default_generator, true> |
| { |
| typedef typename term_traits<T &>::value_type value_type; |
| typedef proto::basic_expr<proto::tag::terminal, term<value_type>, 0> result_type; |
| |
| result_type operator()(T &t) const |
| { |
| return result_type::make(t); |
| } |
| }; |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename T, typename Generator, bool WantsBasicExpr> |
| struct as_child; |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename T, typename Generator> |
| struct as_child<T, Generator, false> |
| { |
| #if BOOST_WORKAROUND(BOOST_MSVC, == 1310) |
| typedef typename term_traits<T &>::reference reference; |
| #else |
| typedef T &reference; |
| #endif |
| typedef proto::expr<proto::tag::terminal, term<reference>, 0> expr_type; |
| typedef typename Generator::template result<Generator(expr_type)>::type result_type; |
| |
| result_type operator()(T &t) const |
| { |
| return Generator()(expr_type::make(t)); |
| } |
| }; |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename T, typename Generator> |
| struct as_child<T, Generator, true> |
| { |
| #if BOOST_WORKAROUND(BOOST_MSVC, == 1310) |
| typedef typename term_traits<T &>::reference reference; |
| #else |
| typedef T &reference; |
| #endif |
| typedef proto::basic_expr<proto::tag::terminal, term<reference>, 0> expr_type; |
| typedef typename Generator::template result<Generator(expr_type)>::type result_type; |
| |
| result_type operator()(T &t) const |
| { |
| return Generator()(expr_type::make(t)); |
| } |
| }; |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename T> |
| struct as_child<T, proto::default_generator, false> |
| { |
| #if BOOST_WORKAROUND(BOOST_MSVC, == 1310) |
| typedef typename term_traits<T &>::reference reference; |
| #else |
| typedef T &reference; |
| #endif |
| typedef proto::expr<proto::tag::terminal, term<reference>, 0> result_type; |
| |
| result_type operator()(T &t) const |
| { |
| return result_type::make(t); |
| } |
| }; |
| |
| //////////////////////////////////////////////////////////////////////////////////////////////// |
| template<typename T> |
| struct as_child<T, proto::default_generator, true> |
| { |
| #if BOOST_WORKAROUND(BOOST_MSVC, == 1310) |
| typedef typename term_traits<T &>::reference reference; |
| #else |
| typedef T &reference; |
| #endif |
| typedef proto::basic_expr<proto::tag::terminal, term<reference>, 0> result_type; |
| |
| result_type operator()(T &t) const |
| { |
| return result_type::make(t); |
| } |
| }; |
| |
| }}} |
| |
| #endif |