103 lines
2.8 KiB
Plaintext
103 lines
2.8 KiB
Plaintext
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/*=============================================================================
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Copyright (c) 1998-2003 Joel de Guzman
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http://spirit.sourceforge.net/
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Use, modification and distribution is subject to the Boost Software
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License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#if !defined(BOOST_SPIRIT_MATCH_ATTR_TRAITS_IPP)
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#define BOOST_SPIRIT_MATCH_ATTR_TRAITS_IPP
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#include <boost/optional.hpp>
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#include <boost/mpl/bool.hpp>
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#include <boost/mpl/or.hpp>
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#include <boost/type_traits/is_convertible.hpp>
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#include <boost/type_traits/is_same.hpp>
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namespace boost { namespace spirit {
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BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
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namespace impl
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{
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template <typename T>
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struct match_attr_traits
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{
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typedef typename
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boost::optional<T>::reference_const_type
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const_reference;
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// case where src *IS* convertible to T (dest)
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template <typename T2>
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static void
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convert(boost::optional<T>& dest, T2 const& src, mpl::true_)
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{
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dest.reset(src);
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}
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// case where src *IS NOT* convertible to T (dest)
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template <typename T2>
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static void
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convert(boost::optional<T>& dest, T2 const& /*src*/, mpl::false_)
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{
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dest.reset();
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}
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static void
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convert(boost::optional<T>& dest, nil_t/*src*/)
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{
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dest.reset();
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}
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template <typename T2>
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static void
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convert(boost::optional<T>& dest, T2 const& src)
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{
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convert(dest, src, is_convertible<T2, T>());
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}
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template <typename OtherMatchT>
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static void
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copy(boost::optional<T>& dest, OtherMatchT const& src)
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{
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if (src.has_valid_attribute())
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convert(dest, src.value());
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}
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template <typename OtherMatchT>
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static void
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assign(boost::optional<T>& dest, OtherMatchT const& src)
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{
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if (src.has_valid_attribute())
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convert(dest, src.value());
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else
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dest.reset();
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}
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// T is not reference
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template <typename ValueT>
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static void
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set_value(boost::optional<T>& dest, ValueT const& val, mpl::false_)
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{
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dest.reset(val);
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}
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// T is a reference
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template <typename ValueT>
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static void
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set_value(boost::optional<T>& dest, ValueT const& val, mpl::true_)
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{
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dest.get() = val;
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}
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};
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}
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BOOST_SPIRIT_CLASSIC_NAMESPACE_END
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}} // namespace boost::spirit::impl
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#endif
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