1 /*=============================================================================
2     Copyright (c) 2001-2011 Joel de Guzman
3 
4     Distributed under the Boost Software License, Version 1.0. (See accompanying
5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 ==============================================================================*/
7 #if !defined(BOOST_SPIRIT_LAZY_NOVEMBER_04_2008_1157AM)
8 #define BOOST_SPIRIT_LAZY_NOVEMBER_04_2008_1157AM
9 
10 #if defined(_MSC_VER)
11 #pragma once
12 #endif
13 
14 #include <boost/spirit/include/phoenix_core.hpp>
15 #include <boost/proto/proto.hpp>
16 #include <boost/spirit/home/support/modify.hpp>
17 #include <boost/spirit/home/support/detail/is_spirit_tag.hpp>
18 
19 namespace boost { namespace spirit
20 {
21     template <typename Eval>
22     typename proto::terminal<phoenix::actor<Eval> >::type
lazy(phoenix::actor<Eval> const & f)23     lazy(phoenix::actor<Eval> const& f)
24     {
25         return proto::terminal<phoenix::actor<Eval> >::type::make(f);
26     }
27 
28     namespace tag
29     {
30         struct lazy_eval
31         {
32             BOOST_SPIRIT_IS_TAG()
33         };
34     }
35 
36     template <typename Domain>
37     struct is_modifier_directive<Domain, tag::lazy_eval>
38       : mpl::true_ {};
39 }}
40 
41 #endif
42