87 lines
2.6 KiB
C++
87 lines
2.6 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_EPS_MARCH_23_2007_0454PM)
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#define BOOST_SPIRIT_X3_EPS_MARCH_23_2007_0454PM
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#include <boost/spirit/home/x3/core/skip_over.hpp>
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#include <boost/spirit/home/x3/core/parser.hpp>
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#include <boost/spirit/home/x3/support/unused.hpp>
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namespace boost { namespace spirit { namespace x3
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{
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struct rule_context_tag;
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struct semantic_predicate : parser<semantic_predicate>
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{
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typedef unused_type attribute_type;
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static bool const has_attribute = false;
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constexpr semantic_predicate(bool predicate)
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: predicate(predicate) {}
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template <typename Iterator, typename Context, typename Attribute>
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bool parse(Iterator& first, Iterator const& last
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, Context const& context, unused_type, Attribute&) const
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{
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x3::skip_over(first, last, context);
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return predicate;
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}
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bool predicate;
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};
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template <typename F>
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struct lazy_semantic_predicate : parser<lazy_semantic_predicate<F>>
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{
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typedef unused_type attribute_type;
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static bool const has_attribute = false;
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constexpr lazy_semantic_predicate(F f)
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: f(f) {}
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template <typename Iterator, typename Context, typename Attribute>
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bool parse(Iterator& first, Iterator const& last
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, Context const& context, unused_type, Attribute& /* attr */) const
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{
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x3::skip_over(first, last, context);
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return f(x3::get<rule_context_tag>(context));
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}
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F f;
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};
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struct eps_parser : parser<eps_parser>
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{
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typedef unused_type attribute_type;
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static bool const has_attribute = false;
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template <typename Iterator, typename Context
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, typename RuleContext, typename Attribute>
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bool parse(Iterator& first, Iterator const& last
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, Context const& context, RuleContext&, Attribute&) const
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{
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x3::skip_over(first, last, context);
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return true;
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}
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constexpr semantic_predicate operator()(bool predicate) const
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{
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return { predicate };
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}
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template <typename F>
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constexpr lazy_semantic_predicate<F> operator()(F f) const
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{
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return { f };
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}
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};
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constexpr auto eps = eps_parser{};
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}}}
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#endif
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