ceph/src/boost/boost/spirit/home/classic/dynamic/lazy.hpp

   1 /*=============================================================================
   2     Copyright (c) 2003 Joel de Guzman
   3     Copyright (c) 2003 Vaclav Vesely
   4     http://spirit.sourceforge.net/
   5
   6   Distributed under the Boost Software License, Version 1.0. (See accompanying
   7   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8 =============================================================================*/
   9 #ifndef BOOST_SPIRIT_LAZY_HPP
  10 #define BOOST_SPIRIT_LAZY_HPP
  11
  12 ////////////////////////////////////////////////////////////////////////////////
  13 #include <boost/spirit/home/classic/namespace.hpp>
  14 #include <boost/spirit/home/classic/core/parser.hpp>
  15 #include <boost/spirit/home/classic/phoenix/actor.hpp>
  16
  17 ////////////////////////////////////////////////////////////////////////////////
  18
  19 namespace boost { namespace spirit {
  20
  21 BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
  22
  23     ////////////////////////////////////////////////////////////////////////////
  24     //
  25     // lazy_parser, holds phoenix actor which returns a spirit parser.
  26     //
  27     ////////////////////////////////////////////////////////////////////////////
  28
  29     template<class ActorT>
  30     struct lazy_parser : parser<lazy_parser<ActorT> >
  31     {
  32         typedef lazy_parser<ActorT> self_t;
  33         typedef typename ::phoenix::actor_result<
  34             ActorT, ::phoenix::tuple<> >::plain_type actor_result_t;
  35
  36         template<typename ScannerT>
  37         struct result
  38         {
  39             typedef typename
  40                 parser_result<actor_result_t, ScannerT>::type
  41             type;
  42         };
  43
  44         lazy_parser(ActorT const& actor_)
  45         : actor(actor_) {}
  46
  47         template<typename ScannerT>
  48         typename parser_result<self_t, ScannerT>::type
  49         parse(ScannerT const& scan) const
  50         { return actor().parse(scan); }
  51
  52         ActorT actor;
  53     };
  54
  55     //////////////////////////////
  56     // lazy_p, returns lazy_parser
  57     // Usage: lazy_p(actor)
  58     template<class ActorT>
  59     lazy_parser<ActorT> lazy_p(ActorT const& actor)
  60     { return lazy_parser<ActorT>(actor); }
  61
  62 BOOST_SPIRIT_CLASSIC_NAMESPACE_END
  63
  64 }} // namespace BOOST_SPIRIT_CLASSIC_NS
  65
  66 #endif // BOOST_SPIRIT_LAZY_HPP