boost/spirit/home/karma/directive/repeat.hpp
// Copyright (c) 2001-2011 Hartmut Kaiser // Copyright (c) 2001-2011 Joel de Guzman // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) #if !defined(SPIRIT_KARMA_REPEAT_MAY_18_2009_0926AM) #define SPIRIT_KARMA_REPEAT_MAY_18_2009_0926AM #if defined(_MSC_VER) #pragma once #endif #include <boost/spirit/home/karma/meta_compiler.hpp> #include <boost/spirit/home/karma/detail/output_iterator.hpp> #include <boost/spirit/home/karma/detail/get_stricttag.hpp> #include <boost/spirit/home/karma/generator.hpp> #include <boost/spirit/home/karma/auxiliary/lazy.hpp> #include <boost/spirit/home/karma/operator/kleene.hpp> #include <boost/spirit/home/support/container.hpp> #include <boost/spirit/home/support/common_terminals.hpp> #include <boost/spirit/home/support/has_semantic_action.hpp> #include <boost/spirit/home/support/handles_container.hpp> #include <boost/spirit/home/karma/detail/attributes.hpp> #include <boost/spirit/home/support/info.hpp> #include <boost/fusion/include/at.hpp> namespace boost { namespace spirit { /////////////////////////////////////////////////////////////////////////// // Enablers /////////////////////////////////////////////////////////////////////////// template <> struct use_directive<karma::domain, tag::repeat> // enables repeat[p] : mpl::true_ {}; template <typename T> struct use_directive<karma::domain , terminal_ex<tag::repeat // enables repeat(exact)[p] , fusion::vector1<T> > > : mpl::true_ {}; template <typename T> struct use_directive<karma::domain , terminal_ex<tag::repeat // enables repeat(min, max)[p] , fusion::vector2<T, T> > > : mpl::true_ {}; template <typename T> struct use_directive<karma::domain , terminal_ex<tag::repeat // enables repeat(min, inf)[p] , fusion::vector2<T, inf_type> > > : mpl::true_ {}; template <> // enables *lazy* repeat(exact)[p] struct use_lazy_directive< karma::domain , tag::repeat , 1 // arity > : mpl::true_ {}; template <> // enables *lazy* repeat(min, max)[p] struct use_lazy_directive< // and repeat(min, inf)[p] karma::domain , tag::repeat , 2 // arity > : mpl::true_ {}; }} namespace boost { namespace spirit { namespace karma { #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS using spirit::repeat; using spirit::inf; #endif using spirit::repeat_type; using spirit::inf_type; /////////////////////////////////////////////////////////////////////////// // handles repeat(exact)[p] template <typename T> struct exact_iterator { exact_iterator(T const exact) : exact(exact) {} typedef T type; T start() const { return 0; } bool got_max(T i) const { return i >= exact; } bool got_min(T i) const { return i >= exact; } T const exact; private: // silence MSVC warning C4512: assignment operator could not be generated exact_iterator& operator= (exact_iterator const&); }; // handles repeat(min, max)[p] template <typename T> struct finite_iterator { finite_iterator(T const min, T const max) : min BOOST_PREVENT_MACRO_SUBSTITUTION (min) , max BOOST_PREVENT_MACRO_SUBSTITUTION (max) {} typedef T type; T start() const { return 0; } bool got_max(T i) const { return i >= max; } bool got_min(T i) const { return i >= min; } T const min; T const max; private: // silence MSVC warning C4512: assignment operator could not be generated finite_iterator& operator= (finite_iterator const&); }; // handles repeat(min, inf)[p] template <typename T> struct infinite_iterator { infinite_iterator(T const min) : min BOOST_PREVENT_MACRO_SUBSTITUTION (min) {} typedef T type; T start() const { return 0; } bool got_max(T /*i*/) const { return false; } bool got_min(T i) const { return i >= min; } T const min; private: // silence MSVC warning C4512: assignment operator could not be generated infinite_iterator& operator= (infinite_iterator const&); }; /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename LoopIter, typename Strict , typename Derived> struct base_repeat_generator : unary_generator<Derived> { private: // iterate over the given container until its exhausted or the embedded // generator succeeds template <typename F, typename Attribute> bool generate_subject(F f, Attribute const&, mpl::false_) const { // Failing subject generators are just skipped. This allows to // selectively generate items in the provided attribute. while (!f.is_at_end()) { bool r = !f(subject); if (r) return true; if (!f.is_at_end()) f.next(); } return false; } template <typename F, typename Attribute> bool generate_subject(F f, Attribute const&, mpl::true_) const { return !f(subject); } // There is no way to distinguish a failed generator from a // generator to be skipped. We assume the user takes responsibility // for ending the loop if no attribute is specified. template <typename F> bool generate_subject(F f, unused_type, mpl::false_) const { return !f(subject); } public: typedef Subject subject_type; typedef mpl::int_<subject_type::properties::value> properties; // Build a std::vector from the subject's attribute. Note // that build_std_vector may return unused_type if the // subject's attribute is an unused_type. template <typename Context, typename Iterator> struct attribute : traits::build_std_vector< typename traits::attribute_of<Subject, Context, Iterator>::type > {}; base_repeat_generator(Subject const& subject, LoopIter const& iter) : subject(subject), iter(iter) {} template <typename OutputIterator, typename Context, typename Delimiter , typename Attribute> bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d , Attribute const& attr) const { typedef detail::fail_function< OutputIterator, Context, Delimiter > fail_function; typedef typename traits::container_iterator< typename add_const<Attribute>::type >::type iterator_type; typedef typename traits::make_indirect_iterator<iterator_type>::type indirect_iterator_type; typedef detail::pass_container< fail_function, Attribute, indirect_iterator_type, mpl::false_> pass_container; iterator_type it = traits::begin(attr); iterator_type end = traits::end(attr); pass_container pass(fail_function(sink, ctx, d), indirect_iterator_type(it), indirect_iterator_type(end)); // generate the minimal required amount of output typename LoopIter::type i = iter.start(); for (/**/; !pass.is_at_end() && !iter.got_min(i); ++i) { if (!generate_subject(pass, attr, Strict())) { // if we fail before reaching the minimum iteration // required, do not output anything and return false return false; } } if (pass.is_at_end() && !iter.got_min(i)) return false; // insufficient attribute elements // generate some more up to the maximum specified for (/**/; !pass.is_at_end() && !iter.got_max(i); ++i) { if (!generate_subject(pass, attr, Strict())) break; } return detail::sink_is_good(sink); } template <typename Context> info what(Context& context) const { return info("repeat", subject.what(context)); } Subject subject; LoopIter iter; }; template <typename Subject, typename LoopIter> struct repeat_generator : base_repeat_generator< Subject, LoopIter, mpl::false_ , repeat_generator<Subject, LoopIter> > { typedef base_repeat_generator< Subject, LoopIter, mpl::false_, repeat_generator > base_repeat_generator_; repeat_generator(Subject const& subject, LoopIter const& iter) : base_repeat_generator_(subject, iter) {} }; template <typename Subject, typename LoopIter> struct strict_repeat_generator : base_repeat_generator< Subject, LoopIter, mpl::true_ , strict_repeat_generator<Subject, LoopIter> > { typedef base_repeat_generator< Subject, LoopIter, mpl::true_, strict_repeat_generator > base_repeat_generator_; strict_repeat_generator(Subject const& subject, LoopIter const& iter) : base_repeat_generator_(subject, iter) {} }; /////////////////////////////////////////////////////////////////////////// // Generator generators: make_xxx function (objects) /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename Modifiers> struct make_directive<tag::repeat, Subject, Modifiers> { typedef typename mpl::if_< detail::get_stricttag<Modifiers> , strict_kleene<Subject>, kleene<Subject> >::type result_type; result_type operator()(unused_type, Subject const& subject , unused_type) const { return result_type(subject); } }; template <typename T, typename Subject, typename Modifiers> struct make_directive< terminal_ex<tag::repeat, fusion::vector1<T> >, Subject, Modifiers> { typedef exact_iterator<T> iterator_type; typedef typename mpl::if_< detail::get_stricttag<Modifiers> , strict_repeat_generator<Subject, iterator_type> , repeat_generator<Subject, iterator_type> >::type result_type; template <typename Terminal> result_type operator()( Terminal const& term, Subject const& subject, unused_type) const { return result_type(subject, fusion::at_c<0>(term.args)); } }; template <typename T, typename Subject, typename Modifiers> struct make_directive< terminal_ex<tag::repeat, fusion::vector2<T, T> >, Subject, Modifiers> { typedef finite_iterator<T> iterator_type; typedef typename mpl::if_< detail::get_stricttag<Modifiers> , strict_repeat_generator<Subject, iterator_type> , repeat_generator<Subject, iterator_type> >::type result_type; template <typename Terminal> result_type operator()( Terminal const& term, Subject const& subject, unused_type) const { return result_type(subject, iterator_type( fusion::at_c<0>(term.args) , fusion::at_c<1>(term.args) ) ); } }; template <typename T, typename Subject, typename Modifiers> struct make_directive< terminal_ex<tag::repeat , fusion::vector2<T, inf_type> >, Subject, Modifiers> { typedef infinite_iterator<T> iterator_type; typedef typename mpl::if_< detail::get_stricttag<Modifiers> , strict_repeat_generator<Subject, iterator_type> , repeat_generator<Subject, iterator_type> >::type result_type; template <typename Terminal> result_type operator()( Terminal const& term, Subject const& subject, unused_type) const { return result_type(subject, fusion::at_c<0>(term.args)); } }; }}} namespace boost { namespace spirit { namespace traits { /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename LoopIter> struct has_semantic_action<karma::repeat_generator<Subject, LoopIter> > : unary_has_semantic_action<Subject> {}; template <typename Subject, typename LoopIter> struct has_semantic_action<karma::strict_repeat_generator<Subject, LoopIter> > : unary_has_semantic_action<Subject> {}; /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename LoopIter, typename Attribute , typename Context, typename Iterator> struct handles_container< karma::repeat_generator<Subject, LoopIter>, Attribute , Context, Iterator> : mpl::true_ {}; template <typename Subject, typename LoopIter, typename Attribute , typename Context, typename Iterator> struct handles_container< karma::strict_repeat_generator<Subject, LoopIter>, Attribute , Context, Iterator> : mpl::true_ {}; }}} #endif