1 // Copyright 2008-2010 Gordon Woodhull
2 // Distributed under the Boost Software License, Version 1.0.
3 // (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
4 
5 #ifndef BOOST_MSM_MPL_GRAPH_MPL_UTILS_HPP_INCLUDED
6 #define BOOST_MSM_MPL_GRAPH_MPL_UTILS_HPP_INCLUDED
7 
8 #include <boost/mpl/fold.hpp>
9 #include <boost/mpl/map.hpp>
10 #include <boost/mpl/set.hpp>
11 #include <boost/mpl/insert.hpp>
12 #include <boost/mpl/if.hpp>
13 #include <boost/mpl/has_key.hpp>
14 #include <boost/mpl/at.hpp>
15 #include <boost/mpl/and.hpp>
16 
17 namespace boost {
18 namespace msm {
19 namespace mpl_graph {
20 namespace mpl_utils {
21 
22 // This is a grab bag of little metafunctions I expect already
23 // exist under some name I haven't looked for
24 
25 // I figure there are probably better ways to do all of these things,
26 // but for now I'll just write some utilities to isolate my ignorance
27 
28 template<typename Seq>
29 struct as_map :
30     mpl::fold<Seq,
31               mpl::map<>,
32               mpl::insert<mpl::_1, mpl::_2> >
33 {};
34 template<typename Seq>
35 struct as_set :
36     mpl::fold<Seq,
37               mpl::set<>,
38               mpl::insert<mpl::_1, mpl::_2> >
39 {};
40 
41 template<typename AssocSeq, typename Key, typename Default>
42 struct at_or_default :
43     mpl::if_<typename mpl::has_key<AssocSeq, Key>::type,
44              typename mpl::at<AssocSeq, Key>::type,
45              Default>
46 {};
47 
48 template<typename Seq1, typename Seq2>
49 struct set_equal :
50     mpl::fold<Seq2,
51               mpl::true_,
52               mpl::and_<mpl::_1,
53                         mpl::has_key<typename as_set<Seq1>::type,
54                                      mpl::_2 > > >
55 {};
56 
57 }
58 }
59 }
60 }
61 
62 #endif // BOOST_MSM_MPL_GRAPH_MPL_UTILS_HPP_INCLUDED
63