ceph/src/boost/libs/metaparse/example/regexp/main.cpp

   1 // Copyright Abel Sinkovics (abel@sinkovics.hu)  2011.
   2 // Distributed under the Boost Software License, Version 1.0.
   3 //    (See accompanying file LICENSE_1_0.txt or copy at
   4 //          http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #include <boost/metaparse/foldl_reject_incomplete.hpp>
   7 #include <boost/metaparse/foldl_reject_incomplete1.hpp>
   8 #include <boost/metaparse/lit_c.hpp>
   9 #include <boost/metaparse/transform.hpp>
  10 #include <boost/metaparse/one_char_except_c.hpp>
  11 #include <boost/metaparse/one_of.hpp>
  12 #include <boost/metaparse/always_c.hpp>
  13 #include <boost/metaparse/build_parser.hpp>
  14 #include <boost/metaparse/middle_of.hpp>
  15 #include <boost/metaparse/entire_input.hpp>
  16 #include <boost/metaparse/string.hpp>
  17
  18 #include <boost/detail/iterator.hpp>
  19 #include <boost/xpressive/xpressive.hpp>
  20
  21 #include <boost/mpl/bool.hpp>
  22 #include <boost/mpl/string.hpp>
  23
  24 using boost::metaparse::foldl_reject_incomplete;
  25 using boost::metaparse::foldl_reject_incomplete1;
  26 using boost::metaparse::lit_c;
  27 using boost::metaparse::transform;
  28 using boost::metaparse::build_parser;
  29 using boost::metaparse::one_of;
  30 using boost::metaparse::always_c;
  31 using boost::metaparse::middle_of;
  32 using boost::metaparse::one_char_except_c;
  33 using boost::metaparse::entire_input;
  34
  35 using boost::mpl::c_str;
  36 using boost::mpl::true_;
  37 using boost::mpl::false_;
  38
  39 using boost::xpressive::sregex;
  40 using boost::xpressive::as_xpr;
  41
  42 /*
  43  * Results of parsing
  44  */
  45
  46 template <class T>
  47 struct has_value
  48 {
  49   typedef T type;
  50   static const sregex value;
  51 };
  52
  53 template <class T>
  54 const sregex has_value<T>::value = T::run();
  55
  56 struct r_epsilon : has_value<r_epsilon>
  57 {
  58   static sregex run()
  59   {
  60     return as_xpr("");
  61   }
  62 };
  63
  64 struct r_any_char : has_value<r_any_char>
  65 {
  66   static sregex run()
  67   {
  68     return boost::xpressive::_;
  69   }
  70 };
  71
  72 struct r_char_lit
  73 {
  74   template <class C>
  75   struct apply : has_value<apply<C> >
  76   {
  77     static sregex run()
  78     {
  79       return as_xpr(C::type::value);
  80     }
  81   };
  82 };
  83
  84 struct r_append
  85 {
  86   template <class A, class B>
  87   struct apply : has_value<apply<B, A> >
  88   {
  89     static sregex run()
  90     {
  91       return A::type::run() >> B::type::run();
  92     }
  93   };
  94 };
  95
  96 /*
  97  * The grammar
  98  *
  99  * regexp ::= (bracket_expr | non_bracket_expr)*
 100  * non_bracket_expr ::= '.' | char_lit
 101  * bracket_expr ::= '(' regexp ')'
 102  * char_lit ::= any character except: . ( )
 103  */
 104
 105 typedef
 106   foldl_reject_incomplete1<
 107     one_of<
 108       always_c<'.', r_any_char>,
 109       transform<one_char_except_c<'.', '(', ')'>, r_char_lit>
 110     >,
 111     r_epsilon,
 112     r_append
 113   >
 114   non_bracket_expr;
 115
 116 typedef middle_of<lit_c<'('>, non_bracket_expr, lit_c<')'> > bracket_expr;
 117
 118 typedef
 119   foldl_reject_incomplete<
 120     one_of<bracket_expr, non_bracket_expr>,
 121     r_epsilon,
 122     r_append
 123   >
 124   regexp;
 125
 126 typedef build_parser<entire_input<regexp> > regexp_parser;
 127
 128 void test_string(const std::string& s)
 129 {
 130   using boost::xpressive::regex_match;
 131   using boost::xpressive::smatch;
 132   using boost::mpl::apply_wrap1;
 133
 134   using std::cout;
 135   using std::endl;
 136
 137 #if BOOST_METAPARSE_STD < 2011
 138   typedef boost::metaparse::string<'.','(','b','c',')'> regexp;
 139 #else
 140   typedef BOOST_METAPARSE_STRING(".(bc)") regexp;
 141 #endif
 142
 143   const sregex re = apply_wrap1<regexp_parser, regexp>::type::value;
 144   smatch w;
 145
 146   cout
 147     << s << (regex_match(s, w, re) ? " matches " : " doesn't match ")
 148     << c_str<regexp>::type::value
 149     << endl;
 150 }
 151
 152 int main()
 153 {
 154   test_string("abc");
 155   test_string("aba");
 156 }
 157
 158