64 lines
2.5 KiB
C++
64 lines
2.5 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2014 Joel de Guzman
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#if !defined(BOOST_SPIRIT_X3_ALTERNATIVE_JAN_07_2013_1131AM)
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#define BOOST_SPIRIT_X3_ALTERNATIVE_JAN_07_2013_1131AM
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#include <boost/spirit/home/x3/support/traits/attribute_of_binary.hpp>
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#include <boost/spirit/home/x3/core/parser.hpp>
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#include <boost/spirit/home/x3/operator/detail/alternative.hpp>
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#include <boost/variant/variant_fwd.hpp>
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namespace boost { namespace spirit { namespace x3
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{
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template <typename Left, typename Right>
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struct alternative : binary_parser<Left, Right, alternative<Left, Right>>
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{
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typedef binary_parser<Left, Right, alternative<Left, Right>> base_type;
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constexpr alternative(Left const& left, Right const& right)
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: base_type(left, right) {}
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template <typename Iterator, typename Context, typename RContext>
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bool parse(
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Iterator& first, Iterator const& last
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, Context const& context, RContext& rcontext, unused_type) const
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{
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return this->left.parse(first, last, context, rcontext, unused)
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|| this->right.parse(first, last, context, rcontext, unused);
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}
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template <typename Iterator, typename Context
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, typename RContext, typename Attribute>
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bool parse(
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Iterator& first, Iterator const& last
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, Context const& context, RContext& rcontext, Attribute& attr) const
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{
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return detail::parse_alternative(this->left, first, last, context, rcontext, attr)
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|| detail::parse_alternative(this->right, first, last, context, rcontext, attr);
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}
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};
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template <typename Left, typename Right>
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constexpr alternative<
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typename extension::as_parser<Left>::value_type
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, typename extension::as_parser<Right>::value_type>
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operator|(Left const& left, Right const& right)
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{
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return { as_parser(left), as_parser(right) };
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}
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}}}
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namespace boost { namespace spirit { namespace x3 { namespace traits
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{
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template <typename Left, typename Right, typename Context>
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struct attribute_of<x3::alternative<Left, Right>, Context>
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: x3::detail::attribute_of_binary<boost::variant, x3::alternative, Left, Right, Context> {};
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}}}}
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#endif
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