core/composite/no_actions.hpp

0001 /*=============================================================================
0002     Copyright (c) 1998-2003 Joel de Guzman
0003     Copyright (c) 2003 Vaclav Vesely
0004     http://spirit.sourceforge.net/
0005
0006   Distributed under the Boost Software License, Version 1.0. (See accompanying
0007   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0008 =============================================================================*/
0009 #if !defined(BOOST_SPIRIT_NO_ACTIONS_HPP)
0010 #define BOOST_SPIRIT_NO_ACTIONS_HPP
0011
0012 #include <boost/spirit/home/classic/core/parser.hpp>
0013 #include <boost/spirit/home/classic/core/composite/composite.hpp>
0014 #include <boost/spirit/home/classic/core/non_terminal/rule.hpp>
0015
0016 namespace boost {
0017 namespace spirit {
0018 BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
0019
0020 //-----------------------------------------------------------------------------
0021 // no_actions_action_policy
0022
0023 template<typename BaseT = action_policy>
0024 struct no_actions_action_policy:
0025     public BaseT
0026 {
0027     typedef BaseT base_t;
0028
0029     no_actions_action_policy():
0030         BaseT()
0031     {}
0032
0033     template<typename PolicyT>
0034     no_actions_action_policy(PolicyT const& other):
0035         BaseT(other)
0036     {}
0037
0038     template<typename ActorT, typename AttrT, typename IteratorT>
0039     void
0040     do_action(
0041         ActorT const&       /*actor*/,
0042         AttrT&              /*val*/,
0043         IteratorT const&    /*first*/,
0044         IteratorT const&    /*last*/) const
0045     {}
0046 };
0047
0048 //-----------------------------------------------------------------------------
0049 // no_actions_scanner
0050
0051
0052 namespace detail
0053 {
0054     template <typename ActionPolicy>
0055     struct compute_no_actions_action_policy
0056     {
0057         typedef no_actions_action_policy<ActionPolicy> type;
0058     };
0059
0060     template <typename ActionPolicy>
0061     struct compute_no_actions_action_policy<no_actions_action_policy<ActionPolicy> >
0062     {
0063         typedef no_actions_action_policy<ActionPolicy> type;
0064     };
0065 }
0066
0067 template<typename ScannerT = scanner<> >
0068 struct no_actions_scanner
0069 {
0070     typedef scanner_policies<
0071         typename ScannerT::iteration_policy_t,
0072         typename ScannerT::match_policy_t,
0073         typename detail::compute_no_actions_action_policy<typename ScannerT::action_policy_t>::type
0074     > policies_t;
0075
0076     typedef typename
0077         rebind_scanner_policies<ScannerT, policies_t>::type type;
0078 };
0079
0080 #if BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT > 1
0081
0082 template<typename ScannerT = scanner<> >
0083 struct no_actions_scanner_list
0084 {
0085     typedef
0086         scanner_list<
0087             ScannerT,
0088             typename no_actions_scanner<ScannerT>::type
0089         >
0090             type;
0091 };
0092
0093 #endif // BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT > 1
0094
0095 //-----------------------------------------------------------------------------
0096 // no_actions_parser
0097
0098 struct no_actions_parser_gen;
0099
0100 template<typename ParserT>
0101 struct no_actions_parser:
0102     public unary<ParserT, parser<no_actions_parser<ParserT> > >
0103 {
0104     typedef no_actions_parser<ParserT>      self_t;
0105     typedef unary_parser_category           parser_category_t;
0106     typedef no_actions_parser_gen           parser_generator_t;
0107     typedef unary<ParserT, parser<self_t> > base_t;
0108
0109     template<typename ScannerT>
0110     struct result
0111     {
0112         typedef typename parser_result<ParserT, ScannerT>::type type;
0113     };
0114
0115     no_actions_parser(ParserT const& p)
0116     :   base_t(p)
0117     {}
0118
0119     template<typename ScannerT>
0120     typename result<ScannerT>::type
0121     parse(ScannerT const& scan) const
0122     {
0123         typedef typename no_actions_scanner<ScannerT>::policies_t policies_t;
0124
0125         return this->subject().parse(scan.change_policies(policies_t(scan)));
0126     }
0127 };
0128
0129 //-----------------------------------------------------------------------------
0130 // no_actions_parser_gen
0131
0132 struct no_actions_parser_gen
0133 {
0134     template<typename ParserT>
0135     struct result
0136     {
0137         typedef no_actions_parser<ParserT> type;
0138     };
0139
0140     template<typename ParserT>
0141     static no_actions_parser<ParserT>
0142     generate(parser<ParserT> const& subject)
0143     {
0144         return no_actions_parser<ParserT>(subject.derived());
0145     }
0146
0147     template<typename ParserT>
0148     no_actions_parser<ParserT>
0149     operator[](parser<ParserT> const& subject) const
0150     {
0151         return no_actions_parser<ParserT>(subject.derived());
0152     }
0153 };
0154
0155 //-----------------------------------------------------------------------------
0156 // no_actions_d
0157
0158 const no_actions_parser_gen no_actions_d = no_actions_parser_gen();
0159
0160 //-----------------------------------------------------------------------------
0161 BOOST_SPIRIT_CLASSIC_NAMESPACE_END
0162 } // namespace spirit
0163 } // namespace boost
0164
0165 #endif // !defined(BOOST_SPIRIT_NO_ACTIONS_HPP)