110 lines
3.7 KiB
C++
110 lines
3.7 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2011 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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#ifndef BOOST_SPIRIT_QI_DIRECTIVE_HOLD_HPP
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#define BOOST_SPIRIT_QI_DIRECTIVE_HOLD_HPP
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#if defined(_MSC_VER)
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#pragma once
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#endif
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#include <boost/spirit/home/qi/meta_compiler.hpp>
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#include <boost/spirit/home/qi/skip_over.hpp>
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#include <boost/spirit/home/qi/parser.hpp>
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#include <boost/spirit/home/support/attributes.hpp>
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#include <boost/spirit/home/support/info.hpp>
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#include <boost/spirit/home/support/common_terminals.hpp>
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#include <boost/spirit/home/support/unused.hpp>
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#include <boost/spirit/home/support/has_semantic_action.hpp>
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#include <boost/spirit/home/support/handles_container.hpp>
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namespace boost { namespace spirit
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{
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///////////////////////////////////////////////////////////////////////////
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// Enablers
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///////////////////////////////////////////////////////////////////////////
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template <>
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struct use_directive<qi::domain, tag::hold> // enables hold
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: mpl::true_ {};
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}}
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namespace boost { namespace spirit { namespace qi
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{
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#ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
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using spirit::hold;
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#endif
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using spirit::hold_type;
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template <typename Subject>
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struct hold_directive : unary_parser<hold_directive<Subject> >
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{
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typedef Subject subject_type;
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hold_directive(Subject const& subject_)
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: subject(subject_) {}
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template <typename Context, typename Iterator>
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struct attribute
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{
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typedef typename
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traits::attribute_of<subject_type, Context, Iterator>::type
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type;
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};
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template <typename Iterator, typename Context
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, typename Skipper, typename Attribute>
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bool parse(Iterator& first, Iterator const& last
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, Context& context, Skipper const& skipper, Attribute& attr_) const
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{
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Attribute copy(attr_);
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if (subject.parse(first, last, context, skipper, copy))
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{
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traits::swap_impl(copy, attr_);
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return true;
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}
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return false;
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}
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template <typename Context>
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info what(Context& context) const
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{
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return info("hold", subject.what(context));
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}
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Subject subject;
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};
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///////////////////////////////////////////////////////////////////////////
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// Parser generators: make_xxx function (objects)
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject, typename Modifiers>
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struct make_directive<tag::hold, Subject, Modifiers>
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{
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typedef hold_directive<Subject> result_type;
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result_type operator()(unused_type, Subject const& subject, unused_type) const
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{
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return result_type(subject);
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}
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};
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}}}
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namespace boost { namespace spirit { namespace traits
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{
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject>
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struct has_semantic_action<qi::hold_directive<Subject> >
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: unary_has_semantic_action<Subject> {};
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject, typename Attribute, typename Context
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, typename Iterator>
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struct handles_container<qi::hold_directive<Subject>, Attribute
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, Context, Iterator>
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: unary_handles_container<Subject, Attribute, Context, Iterator> {};
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}}}
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#endif
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