repeat.hpp 13 KB

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  1. // Copyright (c) 2001-2011 Hartmut Kaiser
  2. // Copyright (c) 2001-2011 Joel de Guzman
  3. //
  4. // Distributed under the Boost Software License, Version 1.0. (See accompanying
  5. // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  6. #if !defined(SPIRIT_KARMA_REPEAT_MAY_18_2009_0926AM)
  7. #define SPIRIT_KARMA_REPEAT_MAY_18_2009_0926AM
  8. #if defined(_MSC_VER)
  9. #pragma once
  10. #endif
  11. #include <boost/spirit/home/karma/meta_compiler.hpp>
  12. #include <boost/spirit/home/karma/detail/output_iterator.hpp>
  13. #include <boost/spirit/home/karma/detail/get_stricttag.hpp>
  14. #include <boost/spirit/home/karma/generator.hpp>
  15. #include <boost/spirit/home/karma/auxiliary/lazy.hpp>
  16. #include <boost/spirit/home/karma/operator/kleene.hpp>
  17. #include <boost/spirit/home/support/container.hpp>
  18. #include <boost/spirit/home/support/common_terminals.hpp>
  19. #include <boost/spirit/home/support/has_semantic_action.hpp>
  20. #include <boost/spirit/home/support/handles_container.hpp>
  21. #include <boost/spirit/home/karma/detail/attributes.hpp>
  22. #include <boost/spirit/home/support/info.hpp>
  23. #include <boost/fusion/include/at.hpp>
  24. namespace boost { namespace spirit
  25. {
  26. ///////////////////////////////////////////////////////////////////////////
  27. // Enablers
  28. ///////////////////////////////////////////////////////////////////////////
  29. template <>
  30. struct use_directive<karma::domain, tag::repeat> // enables repeat[p]
  31. : mpl::true_ {};
  32. template <typename T>
  33. struct use_directive<karma::domain
  34. , terminal_ex<tag::repeat // enables repeat(exact)[p]
  35. , fusion::vector1<T> >
  36. > : mpl::true_ {};
  37. template <typename T>
  38. struct use_directive<karma::domain
  39. , terminal_ex<tag::repeat // enables repeat(min, max)[p]
  40. , fusion::vector2<T, T> >
  41. > : mpl::true_ {};
  42. template <typename T>
  43. struct use_directive<karma::domain
  44. , terminal_ex<tag::repeat // enables repeat(min, inf)[p]
  45. , fusion::vector2<T, inf_type> >
  46. > : mpl::true_ {};
  47. template <> // enables *lazy* repeat(exact)[p]
  48. struct use_lazy_directive<
  49. karma::domain
  50. , tag::repeat
  51. , 1 // arity
  52. > : mpl::true_ {};
  53. template <> // enables *lazy* repeat(min, max)[p]
  54. struct use_lazy_directive< // and repeat(min, inf)[p]
  55. karma::domain
  56. , tag::repeat
  57. , 2 // arity
  58. > : mpl::true_ {};
  59. }}
  60. namespace boost { namespace spirit { namespace karma
  61. {
  62. #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
  63. using spirit::repeat;
  64. using spirit::inf;
  65. #endif
  66. using spirit::repeat_type;
  67. using spirit::inf_type;
  68. ///////////////////////////////////////////////////////////////////////////
  69. // handles repeat(exact)[p]
  70. template <typename T>
  71. struct exact_iterator
  72. {
  73. exact_iterator(T const exact)
  74. : exact(exact) {}
  75. typedef T type;
  76. T start() const { return 0; }
  77. bool got_max(T i) const { return i >= exact; }
  78. bool got_min(T i) const { return i >= exact; }
  79. T const exact;
  80. private:
  81. // silence MSVC warning C4512: assignment operator could not be generated
  82. exact_iterator& operator= (exact_iterator const&);
  83. };
  84. // handles repeat(min, max)[p]
  85. template <typename T>
  86. struct finite_iterator
  87. {
  88. finite_iterator(T const min, T const max)
  89. : min BOOST_PREVENT_MACRO_SUBSTITUTION (min)
  90. , max BOOST_PREVENT_MACRO_SUBSTITUTION (max) {}
  91. typedef T type;
  92. T start() const { return 0; }
  93. bool got_max(T i) const { return i >= max; }
  94. bool got_min(T i) const { return i >= min; }
  95. T const min;
  96. T const max;
  97. private:
  98. // silence MSVC warning C4512: assignment operator could not be generated
  99. finite_iterator& operator= (finite_iterator const&);
  100. };
  101. // handles repeat(min, inf)[p]
  102. template <typename T>
  103. struct infinite_iterator
  104. {
  105. infinite_iterator(T const min)
  106. : min BOOST_PREVENT_MACRO_SUBSTITUTION (min) {}
  107. typedef T type;
  108. T start() const { return 0; }
  109. bool got_max(T /*i*/) const { return false; }
  110. bool got_min(T i) const { return i >= min; }
  111. T const min;
  112. private:
  113. // silence MSVC warning C4512: assignment operator could not be generated
  114. infinite_iterator& operator= (infinite_iterator const&);
  115. };
  116. ///////////////////////////////////////////////////////////////////////////
  117. template <typename Subject, typename LoopIter, typename Strict
  118. , typename Derived>
  119. struct base_repeat_generator : unary_generator<Derived>
  120. {
  121. private:
  122. // iterate over the given container until its exhausted or the embedded
  123. // generator succeeds
  124. template <typename F, typename Attribute>
  125. bool generate_subject(F f, Attribute const&, mpl::false_) const
  126. {
  127. // Failing subject generators are just skipped. This allows to
  128. // selectively generate items in the provided attribute.
  129. while (!f.is_at_end())
  130. {
  131. bool r = !f(subject);
  132. if (r)
  133. return true;
  134. if (!f.is_at_end())
  135. f.next();
  136. }
  137. return false;
  138. }
  139. template <typename F, typename Attribute>
  140. bool generate_subject(F f, Attribute const&, mpl::true_) const
  141. {
  142. return !f(subject);
  143. }
  144. // There is no way to distinguish a failed generator from a
  145. // generator to be skipped. We assume the user takes responsibility
  146. // for ending the loop if no attribute is specified.
  147. template <typename F>
  148. bool generate_subject(F f, unused_type, mpl::false_) const
  149. {
  150. return !f(subject);
  151. }
  152. public:
  153. typedef Subject subject_type;
  154. typedef mpl::int_<subject_type::properties::value> properties;
  155. // Build a std::vector from the subject's attribute. Note
  156. // that build_std_vector may return unused_type if the
  157. // subject's attribute is an unused_type.
  158. template <typename Context, typename Iterator>
  159. struct attribute
  160. : traits::build_std_vector<
  161. typename traits::attribute_of<Subject, Context, Iterator>::type
  162. >
  163. {};
  164. base_repeat_generator(Subject const& subject, LoopIter const& iter)
  165. : subject(subject), iter(iter) {}
  166. template <typename OutputIterator, typename Context, typename Delimiter
  167. , typename Attribute>
  168. bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
  169. , Attribute const& attr) const
  170. {
  171. typedef detail::fail_function<
  172. OutputIterator, Context, Delimiter
  173. > fail_function;
  174. typedef typename traits::container_iterator<
  175. typename add_const<Attribute>::type
  176. >::type iterator_type;
  177. typedef
  178. typename traits::make_indirect_iterator<iterator_type>::type
  179. indirect_iterator_type;
  180. typedef detail::pass_container<
  181. fail_function, Attribute, indirect_iterator_type, mpl::false_>
  182. pass_container;
  183. iterator_type it = traits::begin(attr);
  184. iterator_type end = traits::end(attr);
  185. pass_container pass(fail_function(sink, ctx, d),
  186. indirect_iterator_type(it), indirect_iterator_type(end));
  187. // generate the minimal required amount of output
  188. typename LoopIter::type i = iter.start();
  189. for (/**/; !pass.is_at_end() && !iter.got_min(i); ++i)
  190. {
  191. if (!generate_subject(pass, attr, Strict()))
  192. {
  193. // if we fail before reaching the minimum iteration
  194. // required, do not output anything and return false
  195. return false;
  196. }
  197. }
  198. if (pass.is_at_end() && !iter.got_min(i))
  199. return false; // insufficient attribute elements
  200. // generate some more up to the maximum specified
  201. for (/**/; !pass.is_at_end() && !iter.got_max(i); ++i)
  202. {
  203. if (!generate_subject(pass, attr, Strict()))
  204. break;
  205. }
  206. return detail::sink_is_good(sink);
  207. }
  208. template <typename Context>
  209. info what(Context& context) const
  210. {
  211. return info("repeat", subject.what(context));
  212. }
  213. Subject subject;
  214. LoopIter iter;
  215. };
  216. template <typename Subject, typename LoopIter>
  217. struct repeat_generator
  218. : base_repeat_generator<
  219. Subject, LoopIter, mpl::false_
  220. , repeat_generator<Subject, LoopIter> >
  221. {
  222. typedef base_repeat_generator<
  223. Subject, LoopIter, mpl::false_, repeat_generator
  224. > base_repeat_generator_;
  225. repeat_generator(Subject const& subject, LoopIter const& iter)
  226. : base_repeat_generator_(subject, iter) {}
  227. };
  228. template <typename Subject, typename LoopIter>
  229. struct strict_repeat_generator
  230. : base_repeat_generator<
  231. Subject, LoopIter, mpl::true_
  232. , strict_repeat_generator<Subject, LoopIter> >
  233. {
  234. typedef base_repeat_generator<
  235. Subject, LoopIter, mpl::true_, strict_repeat_generator
  236. > base_repeat_generator_;
  237. strict_repeat_generator(Subject const& subject, LoopIter const& iter)
  238. : base_repeat_generator_(subject, iter) {}
  239. };
  240. ///////////////////////////////////////////////////////////////////////////
  241. // Generator generators: make_xxx function (objects)
  242. ///////////////////////////////////////////////////////////////////////////
  243. template <typename Subject, typename Modifiers>
  244. struct make_directive<tag::repeat, Subject, Modifiers>
  245. {
  246. typedef typename mpl::if_<
  247. detail::get_stricttag<Modifiers>
  248. , strict_kleene<Subject>, kleene<Subject>
  249. >::type result_type;
  250. result_type operator()(unused_type, Subject const& subject
  251. , unused_type) const
  252. {
  253. return result_type(subject);
  254. }
  255. };
  256. template <typename T, typename Subject, typename Modifiers>
  257. struct make_directive<
  258. terminal_ex<tag::repeat, fusion::vector1<T> >, Subject, Modifiers>
  259. {
  260. typedef exact_iterator<T> iterator_type;
  261. typedef typename mpl::if_<
  262. detail::get_stricttag<Modifiers>
  263. , strict_repeat_generator<Subject, iterator_type>
  264. , repeat_generator<Subject, iterator_type>
  265. >::type result_type;
  266. template <typename Terminal>
  267. result_type operator()(
  268. Terminal const& term, Subject const& subject, unused_type) const
  269. {
  270. return result_type(subject, fusion::at_c<0>(term.args));
  271. }
  272. };
  273. template <typename T, typename Subject, typename Modifiers>
  274. struct make_directive<
  275. terminal_ex<tag::repeat, fusion::vector2<T, T> >, Subject, Modifiers>
  276. {
  277. typedef finite_iterator<T> iterator_type;
  278. typedef typename mpl::if_<
  279. detail::get_stricttag<Modifiers>
  280. , strict_repeat_generator<Subject, iterator_type>
  281. , repeat_generator<Subject, iterator_type>
  282. >::type result_type;
  283. template <typename Terminal>
  284. result_type operator()(
  285. Terminal const& term, Subject const& subject, unused_type) const
  286. {
  287. return result_type(subject,
  288. iterator_type(
  289. fusion::at_c<0>(term.args)
  290. , fusion::at_c<1>(term.args)
  291. )
  292. );
  293. }
  294. };
  295. template <typename T, typename Subject, typename Modifiers>
  296. struct make_directive<
  297. terminal_ex<tag::repeat
  298. , fusion::vector2<T, inf_type> >, Subject, Modifiers>
  299. {
  300. typedef infinite_iterator<T> iterator_type;
  301. typedef typename mpl::if_<
  302. detail::get_stricttag<Modifiers>
  303. , strict_repeat_generator<Subject, iterator_type>
  304. , repeat_generator<Subject, iterator_type>
  305. >::type result_type;
  306. template <typename Terminal>
  307. result_type operator()(
  308. Terminal const& term, Subject const& subject, unused_type) const
  309. {
  310. return result_type(subject, fusion::at_c<0>(term.args));
  311. }
  312. };
  313. }}}
  314. namespace boost { namespace spirit { namespace traits
  315. {
  316. ///////////////////////////////////////////////////////////////////////////
  317. template <typename Subject, typename LoopIter>
  318. struct has_semantic_action<karma::repeat_generator<Subject, LoopIter> >
  319. : unary_has_semantic_action<Subject> {};
  320. template <typename Subject, typename LoopIter>
  321. struct has_semantic_action<karma::strict_repeat_generator<Subject, LoopIter> >
  322. : unary_has_semantic_action<Subject> {};
  323. ///////////////////////////////////////////////////////////////////////////
  324. template <typename Subject, typename LoopIter, typename Attribute
  325. , typename Context, typename Iterator>
  326. struct handles_container<
  327. karma::repeat_generator<Subject, LoopIter>, Attribute
  328. , Context, Iterator>
  329. : mpl::true_ {};
  330. template <typename Subject, typename LoopIter, typename Attribute
  331. , typename Context, typename Iterator>
  332. struct handles_container<
  333. karma::strict_repeat_generator<Subject, LoopIter>, Attribute
  334. , Context, Iterator>
  335. : mpl::true_ {};
  336. }}}
  337. #endif