| /*============================================================================= |
| Copyright (c) 1998-2003 Joel de Guzman |
| http://spirit.sourceforge.net/ |
| |
| Use, modification and distribution is subject to 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) |
| =============================================================================*/ |
| #if !defined(BOOST_SPIRIT_MATCH_ATTR_TRAITS_IPP) |
| #define BOOST_SPIRIT_MATCH_ATTR_TRAITS_IPP |
| |
| #include <boost/optional.hpp> |
| #include <boost/mpl/bool.hpp> |
| #include <boost/mpl/or.hpp> |
| #include <boost/type_traits/is_convertible.hpp> |
| #include <boost/type_traits/is_same.hpp> |
| |
| namespace boost { namespace spirit { |
| |
| BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN |
| |
| namespace impl |
| { |
| template <typename T> |
| struct match_attr_traits |
| { |
| typedef typename |
| boost::optional<T>::reference_const_type |
| const_reference; |
| |
| // case where src *IS* convertible to T (dest) |
| template <typename T2> |
| static void |
| convert(boost::optional<T>& dest, T2 const& src, mpl::true_) |
| { |
| dest.reset(src); |
| } |
| |
| // case where src *IS NOT* convertible to T (dest) |
| template <typename T2> |
| static void |
| convert(boost::optional<T>& dest, T2 const& /*src*/, mpl::false_) |
| { |
| dest.reset(); |
| } |
| |
| static void |
| convert(boost::optional<T>& dest, nil_t/*src*/) |
| { |
| dest.reset(); |
| } |
| |
| template <typename T2> |
| static void |
| convert(boost::optional<T>& dest, T2 const& src) |
| { |
| convert(dest, src, is_convertible<T2, T>()); |
| } |
| |
| template <typename OtherMatchT> |
| static void |
| copy(boost::optional<T>& dest, OtherMatchT const& src) |
| { |
| if (src.has_valid_attribute()) |
| convert(dest, src.value()); |
| } |
| |
| template <typename OtherMatchT> |
| static void |
| assign(boost::optional<T>& dest, OtherMatchT const& src) |
| { |
| if (src.has_valid_attribute()) |
| convert(dest, src.value()); |
| else |
| dest.reset(); |
| } |
| |
| // T is not reference |
| template <typename ValueT> |
| static void |
| set_value(boost::optional<T>& dest, ValueT const& val, mpl::false_) |
| { |
| dest.reset(val); |
| } |
| |
| // T is a reference |
| template <typename ValueT> |
| static void |
| set_value(boost::optional<T>& dest, ValueT const& val, mpl::true_) |
| { |
| dest.get() = val; |
| } |
| }; |
| |
| } |
| |
| BOOST_SPIRIT_CLASSIC_NAMESPACE_END |
| |
| }} // namespace boost::spirit::impl |
| |
| #endif |
| |