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- /*=============================================================================
- 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
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