paludis  Version 2.6.0
visitor_cast.hh
1 /* vim: set sw=4 sts=4 et foldmethod=syntax : */
2 
3 /*
4  * Copyright (c) 2008, 2009, 2010, 2011 Ciaran McCreesh
5  *
6  * This file is part of the Paludis package manager. Paludis is free software;
7  * you can redistribute it and/or modify it under the terms of the GNU General
8  * Public License version 2, as published by the Free Software Foundation.
9  *
10  * Paludis is distributed in the hope that it will be useful, but WITHOUT ANY
11  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
12  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
13  * details.
14  *
15  * You should have received a copy of the GNU General Public License along with
16  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
17  * Place, Suite 330, Boston, MA 02111-1307 USA
18  */
19 
20 #ifndef PALUDIS_GUARD_PALUDIS_UTIL_VISITOR_CAST_HH
21 #define PALUDIS_GUARD_PALUDIS_UTIL_VISITOR_CAST_HH 1
22 
23 #include <paludis/util/visitor_cast-fwd.hh>
24 #include <paludis/util/visitor.hh>
25 #include <type_traits>
26 
27 namespace paludis
28 {
29  template <typename To_, typename From_>
31  {
32  To_ * visit(To_ & t)
33  {
34  return &t;
35  }
36 
37  To_ * visit(From_ &)
38  {
39  return 0;
40  }
41  };
42 
43  template <typename C_, typename T_>
44  struct CopyConst
45  {
46  typedef T_ Type;
47  };
48 
49  template <typename C_, typename T_>
50  struct CopyConst<const C_, T_>
51  {
52  typedef const T_ Type;
53  };
54 
55  template <typename To_, typename From_, typename>
56  To_ *
57  visitor_cast(From_ & from)
58  {
60  return from.template accept_returning<To_ *>(q);
61  }
62 }
63 
64 #endif
Definition: about_metadata-fwd.hh:23
Definition: visitor_cast.hh:30
Definition: visitor_cast.hh:44