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