/*============================================================================= | |
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 | |