| /*============================================================================= |
| Copyright (c) 2003 Hartmut Kaiser |
| http://spirit.sourceforge.net/ |
| |
| Use, modification and distribution is subject to 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_SELECT_IPP |
| #define BOOST_SPIRIT_SELECT_IPP |
| |
| #include <boost/spirit/home/classic/core/parser.hpp> |
| #include <boost/spirit/home/classic/core/composite/composite.hpp> |
| #include <boost/spirit/home/classic/meta/as_parser.hpp> |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| namespace boost { namespace spirit { |
| |
| BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| namespace impl { |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| template <typename ParserT> |
| struct as_embedded_parser : public as_parser<ParserT> |
| { |
| typedef typename as_parser<ParserT>::type::derived_t::embed_t type; |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| // no implementation here to catch unknown BehaviourT template arguments |
| template <typename ResultT, typename BehaviourT> |
| struct select_match_gen; |
| |
| // implementation for the select_default_no_fail behaviour |
| template <typename ResultT> |
| struct select_match_gen<ResultT, select_default_no_fail> { |
| |
| template <typename ScannerT> |
| static ResultT |
| do_ (ScannerT const &scan) |
| { |
| return scan.create_match(0, -1, scan.first, scan.first); |
| } |
| }; |
| |
| // implementation for the select_default_fail behaviour |
| template <typename ResultT> |
| struct select_match_gen<ResultT, select_default_fail> { |
| |
| template <typename ScannerT> |
| static ResultT |
| do_ (ScannerT const &scan) |
| { |
| return scan.no_match(); |
| } |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| template <int N, typename ResultT, typename TupleT, typename BehaviourT> |
| struct parse_tuple_element { |
| |
| BOOST_STATIC_CONSTANT(int, index = (TupleT::length - N)); |
| |
| template <typename ScannerT> |
| static ResultT |
| do_(TupleT const &t, ScannerT const &scan) |
| { |
| typedef typename ::phoenix::tuple_element<index, TupleT>::type parser_t; |
| typedef typename ScannerT::iterator_t iterator_t; |
| typedef typename parser_result<parser_t, ScannerT>::type result_t; |
| |
| iterator_t save(scan.first); |
| result_t result(t[::phoenix::tuple_index<index>()].parse(scan)); |
| |
| if (result) { |
| return scan.create_match(result.length(), TupleT::length - N, |
| save, scan.first); |
| } |
| scan.first = save; // reset the input stream |
| return parse_tuple_element<N-1, ResultT, TupleT, BehaviourT>:: |
| do_(t, scan); |
| } |
| }; |
| |
| template <typename ResultT, typename TupleT, typename BehaviourT> |
| struct parse_tuple_element<1, ResultT, TupleT, BehaviourT> { |
| |
| BOOST_STATIC_CONSTANT(int, index = (TupleT::length - 1)); |
| |
| template <typename ScannerT> |
| static ResultT |
| do_(TupleT const &t, ScannerT const &scan) |
| { |
| typedef typename ::phoenix::tuple_element<index, TupleT>::type parser_t; |
| typedef typename ScannerT::iterator_t iterator_t; |
| typedef typename parser_result<parser_t, ScannerT>::type result_t; |
| |
| iterator_t save(scan.first); |
| result_t result(t[::phoenix::tuple_index<index>()].parse(scan)); |
| |
| if (result) { |
| return scan.create_match(result.length(), TupleT::length - 1, |
| save, scan.first); |
| } |
| scan.first = save; // reset the input stream |
| return select_match_gen<ResultT, BehaviourT>::do_(scan); |
| } |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| } // namespace impl |
| |
| BOOST_SPIRIT_CLASSIC_NAMESPACE_END |
| |
| }} // namespace boost::spirit |
| |
| #endif // BOOST_SPIRIT_SELECT_IPP |