| // Boost.TypeErasure library |
| // |
| // Copyright 2011 Steven Watanabe |
| // |
| // Distributed under the Boost Software License Version 1.0. (See |
| // accompanying file LICENSE_1_0.txt or copy at |
| // http://www.boost.org/LICENSE_1_0.txt) |
| // |
| // $Id$ |
| |
| #include <boost/type_erasure/operators.hpp> |
| #include <typeinfo> |
| |
| namespace mpl = boost::mpl; |
| using namespace boost::type_erasure; |
| |
| //[concept_map1 |
| /*` |
| Sometimes it is useful to non-intrusively adapt a |
| type to model a concept. For example, suppose that |
| we want to make `std::type_info` model __less_than_comparable. |
| To do this, we simply specialize the concept definition. |
| */ |
| namespace boost { |
| namespace type_erasure { |
| |
| template<> |
| struct less_than_comparable<std::type_info> |
| { |
| static bool apply(const std::type_info& lhs, const std::type_info& rhs) |
| { return lhs.before(rhs) != 0; } |
| }; |
| |
| } |
| } |
| |
| /*` |
| [note Most, but not all of the builtin concepts can be specialized. |
| Constructors, destructors, and RTTI need special treatment from the |
| library and cannot be specialized. Only primitive concepts can |
| be specialized, so the iterator concepts are also out.] |
| */ |
| |
| //] |
| |
| //[concept_map |
| //` (For the source of the examples in this section see |
| //` [@boost:/libs/type_erasure/example/concept_map.cpp concept_map.cpp]) |
| //` [concept_map1] |
| //] |