ceph/src/boost/libs/metaparse/example/meta_hs/grammar.hpp

   1 #ifndef META_HS_GRAMMAR_HPP
   2 #define META_HS_GRAMMAR_HPP
   3
   4 // Copyright Abel Sinkovics (abel@sinkovics.hu)  2012.
   5 // Distributed under the Boost Software License, Version 1.0.
   6 //    (See accompanying file LICENSE_1_0.txt or copy at
   7 //          http://www.boost.org/LICENSE_1_0.txt)
   8
   9 #include <token.hpp>
  10 #include <semantic.hpp>
  11
  12 #include <boost/metaparse/middle_of.hpp>
  13 #include <boost/metaparse/transform.hpp>
  14 #include <boost/metaparse/sequence.hpp>
  15 #include <boost/metaparse/last_of.hpp>
  16 #include <boost/metaparse/one_of.hpp>
  17 #include <boost/metaparse/foldl_reject_incomplete_start_with_parser.hpp>
  18 #include <boost/metaparse/foldr_start_with_parser.hpp>
  19 #include <boost/metaparse/entire_input.hpp>
  20 #include <boost/metaparse/build_parser.hpp>
  21
  22 namespace grammar
  23 {
  24   /*
  25    * The grammar
  26    *
  27    * definition ::= token::name+ token::define expression
  28    * expression ::= cmp_exp
  29    * cmp_exp ::= plus_exp (token::cmp plus_exp)*
  30    * plus_exp ::= mult_exp ((token::plus | token::minus) mult_exp)*
  31    * mult_exp ::= application ((token::mult | token::div) application)*
  32    * application ::= single_exp+
  33    * single_exp ::= if_exp | token::name | token::int_ | bracket_exp
  34    * if_exp ::= token::if_ expression token::then expression token::else_ expression
  35    * bracket_exp ::= token::open_bracket expression token::close_bracket
  36    */
  37
  38   struct expression;
  39
  40   typedef
  41     boost::metaparse::middle_of<
  42       token::open_bracket,
  43       expression,
  44       token::close_bracket
  45     >
  46     bracket_exp;
  47
  48   typedef
  49     boost::metaparse::transform<
  50       boost::metaparse::sequence<
  51         boost::metaparse::last_of<token::if_, expression>,
  52         boost::metaparse::last_of<token::then, expression>,
  53         boost::metaparse::last_of<token::else_, expression>
  54       >,
  55       semantic::if_
  56     >
  57     if_exp;
  58
  59   typedef
  60     boost::metaparse::one_of<
  61       if_exp,
  62       boost::metaparse::transform<token::name, semantic::ref>,
  63       boost::metaparse::transform<token::int_, semantic::value>,
  64       bracket_exp
  65     >
  66     single_exp;
  67
  68   typedef
  69     boost::metaparse::foldl_reject_incomplete_start_with_parser<
  70       single_exp,
  71       single_exp,
  72       semantic::application
  73     >
  74     application;
  75
  76   typedef
  77     boost::metaparse::foldl_reject_incomplete_start_with_parser<
  78       boost::metaparse::sequence<
  79         boost::metaparse::one_of<token::mult, token::div>,
  80         application
  81       >,
  82       application,
  83       semantic::binary_op
  84     >
  85     mult_exp;
  86
  87   typedef
  88     boost::metaparse::foldl_reject_incomplete_start_with_parser<
  89       boost::metaparse::sequence<
  90         boost::metaparse::one_of<token::plus, token::minus>,
  91         mult_exp
  92       >,
  93       mult_exp,
  94       semantic::binary_op
  95     >
  96     plus_exp;
  97
  98   typedef
  99     boost::metaparse::foldl_reject_incomplete_start_with_parser<
 100       boost::metaparse::sequence<token::cmp, plus_exp>,
 101       plus_exp,
 102       semantic::binary_op
 103     >
 104     cmp_exp;
 105
 106   struct expression : cmp_exp {};
 107
 108   typedef
 109     boost::metaparse::transform<
 110       boost::metaparse::sequence<
 111         token::name,
 112         boost::metaparse::foldr_start_with_parser<
 113           token::name,
 114           boost::metaparse::last_of<token::define, expression>,
 115           semantic::lambda
 116         >
 117       >,
 118       semantic::pair
 119     >
 120     definition;
 121
 122   typedef
 123     boost::metaparse::build_parser<
 124       boost::metaparse::entire_input<definition>
 125     >
 126     def_parser;
 127 }
 128
 129 #endif
 130