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   1 /*=============================================================================
   2     Copyright (c) 2002-2003 Joel de Guzman
   3     Copyright (c) 2002-2003 Martin Wille
   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_FOR_HPP
  10 #define BOOST_SPIRIT_FOR_HPP
  11 ////////////////////////////////////////////////////////////////////////////////
  12 #include <boost/spirit/home/classic/namespace.hpp>
  13 #include <boost/spirit/home/classic/core/parser.hpp>
  14 #include <boost/spirit/home/classic/core/composite/composite.hpp>
  15 #include <boost/spirit/home/classic/dynamic/impl/conditions.ipp>
  16
  17 ////////////////////////////////////////////////////////////////////////////////
  18
  19 namespace boost { namespace spirit {
  20
  21 BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
  22
  23     namespace impl
  24     {
  25
  26         template <typename FuncT>
  27         struct for_functor
  28         {
  29             typedef typename boost::call_traits<FuncT>::param_type  param_t;
  30
  31             for_functor(param_t f) : func(f) {}
  32             for_functor() {}
  33             FuncT func;
  34         };
  35
  36         template <typename InitF>
  37         struct for_init_functor : for_functor<InitF>
  38         {
  39             typedef for_functor<InitF>          base_t;
  40             typedef typename base_t::param_t    param_t;
  41
  42             for_init_functor(param_t f) : base_t(f) {}
  43             for_init_functor() : base_t() {}
  44             void init() const { /*return*/ this->func(); }
  45         };
  46
  47         template <typename StepF>
  48         struct for_step_functor : for_functor<StepF>
  49         {
  50             typedef for_functor<StepF>          base_t;
  51             typedef typename base_t::param_t    param_t;
  52
  53             for_step_functor(param_t f) : base_t(f) {}
  54             for_step_functor() : base_t() {}
  55             void step() const { /*return*/ this->func(); }
  56         };
  57
  58         //////////////////////////////////
  59         // for_parser
  60         template
  61         <
  62             typename InitF, typename CondT, typename StepF,
  63             typename ParsableT
  64         >
  65         struct for_parser
  66             : private for_init_functor<InitF>
  67             , private for_step_functor<StepF>
  68             , private condition_evaluator<typename as_parser<CondT>::type>
  69             , public unary
  70             <
  71                 typename as_parser<ParsableT>::type,
  72                 parser< for_parser<InitF, CondT, StepF, ParsableT> >
  73             >
  74         {
  75             typedef for_parser<InitF, CondT, StepF, ParsableT> self_t;
  76             typedef as_parser<CondT>                           cond_as_parser_t;
  77             typedef typename cond_as_parser_t::type            condition_t;
  78             typedef condition_evaluator<condition_t>           eval_t;
  79             typedef as_parser<ParsableT>                       as_parser_t;
  80             typedef typename as_parser_t::type                 parser_t;
  81             typedef unary< parser_t, parser< self_t > >        base_t;
  82
  83
  84             //////////////////////////////
  85             // constructor, saves init, condition and step functors
  86             // for later use the parse member function
  87             for_parser
  88             (
  89                 InitF const &i, CondT const &c, StepF const &s,
  90                 ParsableT const &p
  91             )
  92                 : for_init_functor<InitF>(i)
  93                 , for_step_functor<StepF>(s)
  94                 , eval_t(cond_as_parser_t::convert(c))
  95                 , base_t(as_parser_t::convert(p))
  96             { }
  97
  98             for_parser()
  99                 : for_init_functor<InitF>()
 100                 , for_step_functor<StepF>()
 101                 , eval_t()
 102                 , base_t()
 103             {}
 104
 105             //////////////////////////////
 106             // parse member function
 107             template <typename ScannerT>
 108             typename parser_result<self_t, ScannerT>::type
 109             parse(ScannerT const &scan) const
 110             {
 111                 typedef typename parser_result<self_t, ScannerT>::type
 112                     result_t;
 113                 typedef typename parser_result<parser_t, ScannerT>::type
 114                     body_result_t;
 115
 116                 typename ScannerT::iterator_t save(scan.first);
 117
 118                 std::size_t length = 0;
 119                 int eval_length = 0;
 120
 121                 this->init();
 122                 while ((eval_length = this->evaluate(scan))>=0)
 123                 {
 124                     length += eval_length;
 125                     body_result_t tmp(this->subject().parse(scan));
 126                     if (tmp)
 127                     {
 128                         length+=tmp.length();
 129                     }
 130                     else
 131                     {
 132                         return scan.no_match();
 133                     }
 134                     this->step();
 135                 }
 136
 137                 BOOST_SPIRIT_CLASSIC_NS::nil_t attr;
 138                 return scan.create_match
 139                     (length, attr, save, scan.first);
 140             }
 141         };
 142
 143         //////////////////////////////////
 144         // for_parser_gen generates takes the body parser in brackets
 145         // and returns the for_parser
 146         template <typename InitF, typename CondT, typename StepF>
 147         struct for_parser_gen
 148         {
 149             for_parser_gen(InitF const &i, CondT const &c, StepF const &s)
 150                 : init(i)
 151                 , condition(c)
 152                 , step(s)
 153             {}
 154
 155             template <typename ParsableT>
 156             for_parser<InitF, CondT, StepF, ParsableT>
 157             operator[](ParsableT const &p) const
 158             {
 159                 return for_parser<InitF, CondT, StepF, ParsableT>
 160                     (init, condition, step, p);
 161             }
 162
 163             InitF const &init;
 164             CondT const &condition;
 165             StepF const &step;
 166         };
 167     } // namespace impl
 168
 169     //////////////////////////////
 170     // for_p, returns for-parser generator
 171     // Usage: spirit::for_p(init-ftor, condition, step-ftor)[body]
 172     template
 173     <
 174         typename InitF, typename ConditionT, typename StepF
 175     >
 176     impl::for_parser_gen<InitF, ConditionT, StepF>
 177     for_p(InitF const &init_f, ConditionT const &condition, StepF const &step_f)
 178     {
 179         return impl::for_parser_gen<InitF, ConditionT, StepF>
 180             (init_f, condition, step_f);
 181     }
 182
 183 BOOST_SPIRIT_CLASSIC_NAMESPACE_END
 184
 185 }} // namespace BOOST_SPIRIT_CLASSIC_NS
 186
 187 #endif // BOOST_SPIRIT_FOR_HPP