1 ///////////////////////////////////////////////////////////////////////////////
3 /// Proto callables Fusion pop_back
5 // Copyright 2010 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)
9 #ifndef BOOST_PROTO_FUNCTIONAL_FUSION_POP_BACK_HPP_EAN_11_27_2010
10 #define BOOST_PROTO_FUNCTIONAL_FUSION_POP_BACK_HPP_EAN_11_27_2010
12 #include <boost/fusion/include/begin.hpp>
13 #include <boost/fusion/include/end.hpp>
14 #include <boost/fusion/include/prior.hpp>
15 #include <boost/fusion/include/pop_back.hpp>
16 #include <boost/proto/proto_fwd.hpp>
18 namespace boost { namespace proto { namespace functional
20 /// \brief A PolymorphicFunctionObject type that invokes the
21 /// \c fusion::pop_back() algorithm on its argument.
23 /// A PolymorphicFunctionObject type that invokes the
24 /// \c fusion::pop_back() algorithm on its argument.
27 BOOST_PROTO_CALLABLE()
29 template<typename Sig>
32 template<typename This, typename Seq>
33 struct result<This(Seq)>
34 : result<This(Seq const &)>
37 template<typename This, typename Seq>
38 struct result<This(Seq &)>
39 : fusion::result_of::pop_back<Seq>
42 template<typename Seq>
43 typename fusion::result_of::pop_back<Seq>::type
44 operator ()(Seq &seq) const
46 // Work around a const-correctness issue in Fusion
47 typedef typename fusion::result_of::pop_back<Seq>::type result_type;
48 return result_type(fusion::begin(seq), fusion::prior(fusion::end(seq)));
51 template<typename Seq>
52 typename fusion::result_of::pop_back<Seq const>::type
53 operator ()(Seq const &seq) const
55 return fusion::pop_back(seq);