1 ///////////////////////////////////////////////////////////////////////////////
3 /// Contains definition of the as_expr\<\> and as_child\<\> helper class
4 /// templates used to implement proto::domain's as_expr\<\> and as_child\<\>
7 // Copyright 2010 Eric Niebler. Distributed under the Boost
8 // Software License, Version 1.0. (See accompanying file
9 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
11 #ifndef BOOST_PROTO_DETAIL_AS_EXPR_HPP_EAN_06_09_2010
12 #define BOOST_PROTO_DETAIL_AS_EXPR_HPP_EAN_06_09_2010
14 #include <boost/config.hpp>
15 #include <boost/detail/workaround.hpp>
16 #include <boost/type_traits/remove_const.hpp>
17 #include <boost/proto/proto_fwd.hpp>
18 #include <boost/proto/args.hpp>
20 namespace boost { namespace proto { namespace detail
23 ////////////////////////////////////////////////////////////////////////////////////////////////
24 template<typename Generator>
27 typedef Generator type;
30 template<typename Generator>
31 struct base_generator<use_basic_expr<Generator> >
33 typedef Generator type;
36 ////////////////////////////////////////////////////////////////////////////////////////////////
37 template<typename T, typename Generator, bool WantsBasicExpr>
40 ////////////////////////////////////////////////////////////////////////////////////////////////
41 template<typename T, typename Generator>
42 struct as_expr<T, Generator, false>
44 typedef typename term_traits<T &>::value_type value_type;
45 typedef proto::expr<proto::tag::terminal, term<value_type>, 0> expr_type;
46 typedef typename Generator::template result<Generator(expr_type)>::type result_type;
49 result_type operator()(T &t) const
51 return Generator()(expr_type::make(t));
55 ////////////////////////////////////////////////////////////////////////////////////////////////
56 template<typename T, typename Generator>
57 struct as_expr<T, Generator, true>
59 typedef typename term_traits<T &>::value_type value_type;
60 typedef proto::basic_expr<proto::tag::terminal, term<value_type>, 0> expr_type;
61 typedef typename Generator::template result<Generator(expr_type)>::type result_type;
64 result_type operator()(T &t) const
66 return Generator()(expr_type::make(t));
70 ////////////////////////////////////////////////////////////////////////////////////////////////
72 struct as_expr<T, proto::default_generator, false>
74 typedef typename term_traits<T &>::value_type value_type;
75 typedef proto::expr<proto::tag::terminal, term<value_type>, 0> result_type;
78 result_type operator()(T &t) const
80 return result_type::make(t);
84 ////////////////////////////////////////////////////////////////////////////////////////////////
86 struct as_expr<T, proto::default_generator, true>
88 typedef typename term_traits<T &>::value_type value_type;
89 typedef proto::basic_expr<proto::tag::terminal, term<value_type>, 0> result_type;
92 result_type operator()(T &t) const
94 return result_type::make(t);
98 ////////////////////////////////////////////////////////////////////////////////////////////////
99 template<typename T, typename Generator, bool WantsBasicExpr>
102 ////////////////////////////////////////////////////////////////////////////////////////////////
103 template<typename T, typename Generator>
104 struct as_child<T, Generator, false>
106 #if BOOST_WORKAROUND(BOOST_MSVC, == 1310)
107 typedef typename term_traits<T &>::reference reference;
109 typedef T &reference;
111 typedef proto::expr<proto::tag::terminal, term<reference>, 0> expr_type;
112 typedef typename Generator::template result<Generator(expr_type)>::type result_type;
115 result_type operator()(T &t) const
117 return Generator()(expr_type::make(t));
121 ////////////////////////////////////////////////////////////////////////////////////////////////
122 template<typename T, typename Generator>
123 struct as_child<T, Generator, true>
125 #if BOOST_WORKAROUND(BOOST_MSVC, == 1310)
126 typedef typename term_traits<T &>::reference reference;
128 typedef T &reference;
130 typedef proto::basic_expr<proto::tag::terminal, term<reference>, 0> expr_type;
131 typedef typename Generator::template result<Generator(expr_type)>::type result_type;
134 result_type operator()(T &t) const
136 return Generator()(expr_type::make(t));
140 ////////////////////////////////////////////////////////////////////////////////////////////////
142 struct as_child<T, proto::default_generator, false>
144 #if BOOST_WORKAROUND(BOOST_MSVC, == 1310)
145 typedef typename term_traits<T &>::reference reference;
147 typedef T &reference;
149 typedef proto::expr<proto::tag::terminal, term<reference>, 0> result_type;
152 result_type operator()(T &t) const
154 return result_type::make(t);
158 ////////////////////////////////////////////////////////////////////////////////////////////////
160 struct as_child<T, proto::default_generator, true>
162 #if BOOST_WORKAROUND(BOOST_MSVC, == 1310)
163 typedef typename term_traits<T &>::reference reference;
165 typedef T &reference;
167 typedef proto::basic_expr<proto::tag::terminal, term<reference>, 0> result_type;
170 result_type operator()(T &t) const
172 return result_type::make(t);