mini_xml3.cpp 7.3 KB

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  1. /*=============================================================================
  2. Copyright (c) 2001-2010 Joel de Guzman
  3. Distributed under the Boost Software License, Version 1.0. (See accompanying
  4. file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  5. =============================================================================*/
  6. ///////////////////////////////////////////////////////////////////////////////
  7. //
  8. // A mini XML-like parser
  9. //
  10. // [ JDG March 25, 2007 ] spirit2
  11. //
  12. ///////////////////////////////////////////////////////////////////////////////
  13. #include <boost/config/warning_disable.hpp>
  14. #include <boost/spirit/include/qi.hpp>
  15. #include <boost/spirit/include/phoenix_core.hpp>
  16. #include <boost/spirit/include/phoenix_operator.hpp>
  17. #include <boost/spirit/include/phoenix_fusion.hpp>
  18. #include <boost/spirit/include/phoenix_stl.hpp>
  19. #include <boost/spirit/include/phoenix_object.hpp>
  20. #include <boost/fusion/include/adapt_struct.hpp>
  21. #include <boost/variant/recursive_variant.hpp>
  22. #include <boost/foreach.hpp>
  23. #include <iostream>
  24. #include <fstream>
  25. #include <string>
  26. #include <vector>
  27. namespace client
  28. {
  29. namespace fusion = boost::fusion;
  30. namespace phoenix = boost::phoenix;
  31. namespace qi = boost::spirit::qi;
  32. namespace ascii = boost::spirit::ascii;
  33. ///////////////////////////////////////////////////////////////////////////
  34. // Our mini XML tree representation
  35. ///////////////////////////////////////////////////////////////////////////
  36. struct mini_xml;
  37. typedef
  38. boost::variant<
  39. boost::recursive_wrapper<mini_xml>
  40. , std::string
  41. >
  42. mini_xml_node;
  43. struct mini_xml
  44. {
  45. std::string name; // tag name
  46. std::vector<mini_xml_node> children; // children
  47. };
  48. }
  49. // We need to tell fusion about our mini_xml struct
  50. // to make it a first-class fusion citizen
  51. BOOST_FUSION_ADAPT_STRUCT(
  52. client::mini_xml,
  53. (std::string, name)
  54. (std::vector<client::mini_xml_node>, children)
  55. )
  56. namespace client
  57. {
  58. ///////////////////////////////////////////////////////////////////////////
  59. // Print out the mini xml tree
  60. ///////////////////////////////////////////////////////////////////////////
  61. int const tabsize = 4;
  62. void tab(int indent)
  63. {
  64. for (int i = 0; i < indent; ++i)
  65. std::cout << ' ';
  66. }
  67. struct mini_xml_printer
  68. {
  69. mini_xml_printer(int indent = 0)
  70. : indent(indent)
  71. {
  72. }
  73. void operator()(mini_xml const& xml) const;
  74. int indent;
  75. };
  76. struct mini_xml_node_printer : boost::static_visitor<>
  77. {
  78. mini_xml_node_printer(int indent = 0)
  79. : indent(indent)
  80. {
  81. }
  82. void operator()(mini_xml const& xml) const
  83. {
  84. mini_xml_printer(indent+tabsize)(xml);
  85. }
  86. void operator()(std::string const& text) const
  87. {
  88. tab(indent+tabsize);
  89. std::cout << "text: \"" << text << '"' << std::endl;
  90. }
  91. int indent;
  92. };
  93. void mini_xml_printer::operator()(mini_xml const& xml) const
  94. {
  95. tab(indent);
  96. std::cout << "tag: " << xml.name << std::endl;
  97. tab(indent);
  98. std::cout << '{' << std::endl;
  99. BOOST_FOREACH(mini_xml_node const& node, xml.children)
  100. {
  101. boost::apply_visitor(mini_xml_node_printer(indent), node);
  102. }
  103. tab(indent);
  104. std::cout << '}' << std::endl;
  105. }
  106. ///////////////////////////////////////////////////////////////////////////
  107. // Our mini XML grammar definition
  108. ///////////////////////////////////////////////////////////////////////////
  109. //[tutorial_xml3_grammar
  110. template <typename Iterator>
  111. struct mini_xml_grammar
  112. : qi::grammar<Iterator, mini_xml(), qi::locals<std::string>, ascii::space_type>
  113. {
  114. mini_xml_grammar()
  115. : mini_xml_grammar::base_type(xml, "xml")
  116. {
  117. using qi::lit;
  118. using qi::lexeme;
  119. using qi::on_error;
  120. using qi::fail;
  121. using ascii::char_;
  122. using ascii::string;
  123. using namespace qi::labels;
  124. using phoenix::construct;
  125. using phoenix::val;
  126. text %= lexeme[+(char_ - '<')];
  127. node %= xml | text;
  128. start_tag %=
  129. '<'
  130. >> !lit('/')
  131. > lexeme[+(char_ - '>')]
  132. > '>'
  133. ;
  134. end_tag =
  135. "</"
  136. > lit(_r1)
  137. > '>'
  138. ;
  139. xml %=
  140. start_tag[_a = _1]
  141. > *node
  142. > end_tag(_a)
  143. ;
  144. xml.name("xml");
  145. node.name("node");
  146. text.name("text");
  147. start_tag.name("start_tag");
  148. end_tag.name("end_tag");
  149. on_error<fail>
  150. (
  151. xml
  152. , std::cout
  153. << val("Error! Expecting ")
  154. << _4 // what failed?
  155. << val(" here: \"")
  156. << construct<std::string>(_3, _2) // iterators to error-pos, end
  157. << val("\"")
  158. << std::endl
  159. );
  160. }
  161. qi::rule<Iterator, mini_xml(), qi::locals<std::string>, ascii::space_type> xml;
  162. qi::rule<Iterator, mini_xml_node(), ascii::space_type> node;
  163. qi::rule<Iterator, std::string(), ascii::space_type> text;
  164. qi::rule<Iterator, std::string(), ascii::space_type> start_tag;
  165. qi::rule<Iterator, void(std::string), ascii::space_type> end_tag;
  166. };
  167. //]
  168. }
  169. ///////////////////////////////////////////////////////////////////////////////
  170. // Main program
  171. ///////////////////////////////////////////////////////////////////////////////
  172. int main(int argc, char **argv)
  173. {
  174. char const* filename;
  175. if (argc > 1)
  176. {
  177. filename = argv[1];
  178. }
  179. else
  180. {
  181. std::cerr << "Error: No input file provided." << std::endl;
  182. return 1;
  183. }
  184. std::ifstream in(filename, std::ios_base::in);
  185. if (!in)
  186. {
  187. std::cerr << "Error: Could not open input file: "
  188. << filename << std::endl;
  189. return 1;
  190. }
  191. std::string storage; // We will read the contents here.
  192. in.unsetf(std::ios::skipws); // No white space skipping!
  193. std::copy(
  194. std::istream_iterator<char>(in),
  195. std::istream_iterator<char>(),
  196. std::back_inserter(storage));
  197. typedef client::mini_xml_grammar<std::string::const_iterator> mini_xml_grammar;
  198. mini_xml_grammar xml; // Our grammar
  199. client::mini_xml ast; // Our tree
  200. using boost::spirit::ascii::space;
  201. std::string::const_iterator iter = storage.begin();
  202. std::string::const_iterator end = storage.end();
  203. bool r = phrase_parse(iter, end, xml, space, ast);
  204. if (r && iter == end)
  205. {
  206. std::cout << "-------------------------\n";
  207. std::cout << "Parsing succeeded\n";
  208. std::cout << "-------------------------\n";
  209. client::mini_xml_printer printer;
  210. printer(ast);
  211. return 0;
  212. }
  213. else
  214. {
  215. std::cout << "-------------------------\n";
  216. std::cout << "Parsing failed\n";
  217. std::cout << "-------------------------\n";
  218. return 1;
  219. }
  220. }