ceph/src/boost/libs/spirit/classic/example/fundamental/position_iterator/position_iterator.cpp

   1 /*=============================================================================
   2     Copyright (c) 2002 Juan Carlos Arevalo-Baeza
   3     http://spirit.sourceforge.net/
   4
   5     Use, modification and distribution is subject to the Boost Software
   6     License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   7     http://www.boost.org/LICENSE_1_0.txt)
   8 =============================================================================*/
   9 ///////////////////////////////////////////////////////////////////////////////
  10 //
  11 //  A parser for a comma separated list of numbers,
  12 //  with positional error reporting
  13 //  See the "Position Iterator" chapter in the User's Guide.
  14 //
  15 //  [ JCAB 9/28/2002 ]
  16 //
  17 ///////////////////////////////////////////////////////////////////////////////
  18 #include <boost/spirit/include/classic_core.hpp>
  19 #include <boost/spirit/include/classic_position_iterator.hpp>
  20 #include <boost/spirit/include/classic_functor_parser.hpp>
  21 #include <iostream>
  22 #include <fstream>
  23 #include <vector>
  24
  25 ///////////////////////////////////////////////////////////////////////////////
  26 using namespace std;
  27 using namespace BOOST_SPIRIT_CLASSIC_NS;
  28
  29 ///////////////////////////////////////////////////////////////////////////////
  30 //
  31 //  Our error reporting parsers
  32 //
  33 ///////////////////////////////////////////////////////////////////////////////
  34 std::ostream& operator<<(std::ostream& out, file_position const& lc)
  35 {
  36     return out <<
  37             "\nFile:\t" << lc.file <<
  38             "\nLine:\t" << lc.line <<
  39             "\nCol:\t" << lc.column << endl;
  40 }
  41
  42 struct error_report_parser {
  43     char const* eol_msg;
  44     char const* msg;
  45
  46     error_report_parser(char const* eol_msg_, char const* msg_):
  47         eol_msg(eol_msg_),
  48         msg    (msg_)
  49     {}
  50
  51     typedef nil_t result_t;
  52
  53     template <typename ScannerT>
  54     int
  55     operator()(ScannerT const& scan, result_t& /*result*/) const
  56     {
  57         if (scan.at_end()) {
  58             if (eol_msg) {
  59                 file_position fpos = scan.first.get_position();
  60                 cerr << fpos << eol_msg << endl;
  61             }
  62         } else {
  63             if (msg) {
  64                 file_position fpos = scan.first.get_position();
  65                 cerr << fpos << msg << endl;
  66             }
  67         }
  68
  69         return -1; // Fail.
  70     }
  71
  72 };
  73 typedef functor_parser<error_report_parser> error_report_p;
  74
  75 error_report_p
  76 error_badnumber_or_eol =
  77     error_report_parser(
  78         "Expecting a number, but found the end of the file\n",
  79         "Expecting a number, but found something else\n"
  80     );
  81
  82 error_report_p
  83 error_badnumber =
  84     error_report_parser(
  85         0,
  86         "Expecting a number, but found something else\n"
  87     );
  88
  89 error_report_p
  90 error_comma =
  91     error_report_parser(
  92         0,
  93         "Expecting a comma, but found something else\n"
  94     );
  95
  96 ///////////////////////////////////////////////////////////////////////////////
  97 //
  98 //  Our comma separated list parser
  99 //
 100 ///////////////////////////////////////////////////////////////////////////////
 101 bool
 102 parse_numbers(char const* filename, char const* str, vector<double>& v)
 103 {
 104     typedef position_iterator<char const*> iterator_t;
 105     iterator_t begin(str, str + strlen(str), filename);
 106     iterator_t end;
 107     begin.set_tabchars(8);
 108     return parse(begin, end,
 109
 110         //  Begin grammar
 111         (
 112             (real_p[push_back_a(v)] | error_badnumber)
 113          >> *(
 114                 (',' | error_comma)
 115              >> (real_p[push_back_a(v)] | error_badnumber_or_eol)
 116             )
 117         )
 118         ,
 119         //  End grammar
 120
 121         space_p).full;
 122 }
 123
 124 ////////////////////////////////////////////////////////////////////////////
 125 //
 126 //  Main program
 127 //
 128 ////////////////////////////////////////////////////////////////////////////
 129 int
 130 main(int argc, char **argv)
 131 {
 132     cout << "/////////////////////////////////////////////////////////\n\n";
 133     cout << "\tAn error-reporting parser for Spirit...\n\n";
 134     cout << "Parses a comma separated list of numbers from a file.\n";
 135     cout << "The numbers will be inserted in a vector of numbers\n\n";
 136     cout << "/////////////////////////////////////////////////////////\n\n";
 137
 138     char str[65536];
 139     char const* filename;
 140
 141     if (argc > 1) {
 142         filename = argv[1];
 143         ifstream file(filename);
 144         file.get(str, sizeof(str), '\0');
 145     } else {
 146         filename = "<cin>";
 147         cin.get(str, sizeof(str), '\0');
 148     }
 149
 150     vector<double> v;
 151     if (parse_numbers(filename, str, v))
 152     {
 153         cout << "-------------------------\n";
 154         cout << "Parsing succeeded\n";
 155         cout << str << " Parses OK: " << endl;
 156
 157         for (vector<double>::size_type i = 0; i < v.size(); ++i)
 158             cout << i << ": " << v[i] << endl;
 159
 160         cout << "-------------------------\n";
 161     }
 162     else
 163     {
 164         cout << "-------------------------\n";
 165         cout << "Parsing failed\n";
 166         cout << "-------------------------\n";
 167     }
 168
 169     cout << "Bye... :-) \n\n";
 170     return 0;
 171 }
 172
 173