ceph/src/boost/libs/spirit/include/boost/spirit/home/karma/operator/kleene.hpp

   1 //  Copyright (c) 2001-2011 Joel de Guzman
   2 //  Copyright (c) 2001-2011 Hartmut Kaiser
   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
   7 #if !defined(BOOST_SPIRIT_KARMA_KLEENE_MAR_03_2007_0337AM)
   8 #define BOOST_SPIRIT_KARMA_KLEENE_MAR_03_2007_0337AM
   9
  10 #if defined(_MSC_VER)
  11 #pragma once
  12 #endif
  13
  14 #include <boost/spirit/home/karma/domain.hpp>
  15 #include <boost/spirit/home/karma/generator.hpp>
  16 #include <boost/spirit/home/karma/meta_compiler.hpp>
  17 #include <boost/spirit/home/karma/detail/output_iterator.hpp>
  18 #include <boost/spirit/home/karma/detail/indirect_iterator.hpp>
  19 #include <boost/spirit/home/karma/detail/get_stricttag.hpp>
  20 #include <boost/spirit/home/karma/detail/pass_container.hpp>
  21 #include <boost/spirit/home/karma/detail/fail_function.hpp>
  22 #include <boost/spirit/home/support/info.hpp>
  23 #include <boost/spirit/home/support/unused.hpp>
  24 #include <boost/spirit/home/support/container.hpp>
  25 #include <boost/spirit/home/support/handles_container.hpp>
  26 #include <boost/spirit/home/karma/detail/attributes.hpp>
  27
  28 #include <boost/type_traits/add_const.hpp>
  29
  30 namespace boost { namespace spirit
  31 {
  32     ///////////////////////////////////////////////////////////////////////////
  33     // Enablers
  34     ///////////////////////////////////////////////////////////////////////////
  35     template <>
  36     struct use_operator<karma::domain, proto::tag::dereference> // enables *g
  37       : mpl::true_ {};
  38 }}
  39
  40 ///////////////////////////////////////////////////////////////////////////////
  41 namespace boost { namespace spirit { namespace karma
  42 {
  43     template <typename Subject, typename Strict, typename Derived>
  44     struct base_kleene : unary_generator<Derived>
  45     {
  46     private:
  47         // Ignore return value in relaxed mode (failing subject generators
  48         // are just skipped). This allows to selectively generate items in
  49         // the provided attribute.
  50         template <typename F, typename Attribute>
  51         bool generate_subject(F f, Attribute const&, mpl::false_) const
  52         {
  53             bool r = !f(subject);
  54             if (!r && !f.is_at_end())
  55                 f.next();
  56             return true;
  57         }
  58
  59         template <typename F, typename Attribute>
  60         bool generate_subject(F f, Attribute const&, mpl::true_) const
  61         {
  62             return !f(subject);
  63         }
  64
  65         // There is no way to distinguish a failed generator from a
  66         // generator to be skipped. We assume the user takes responsibility
  67         // for ending the loop if no attribute is specified.
  68         template <typename F>
  69         bool generate_subject(F f, unused_type, mpl::false_) const
  70         {
  71             return !f(subject);
  72         }
  73
  74 //         template <typename F>
  75 //         bool generate_subject(F f, unused_type, mpl::true_) const
  76 //         {
  77 //             return !f(subject);
  78 //         }
  79
  80     public:
  81         typedef Subject subject_type;
  82         typedef typename subject_type::properties properties;
  83
  84         // Build a std::vector from the subject's attribute. Note
  85         // that build_std_vector may return unused_type if the
  86         // subject's attribute is an unused_type.
  87         template <typename Context, typename Iterator>
  88         struct attribute
  89           : traits::build_std_vector<
  90                 typename traits::attribute_of<Subject, Context, Iterator>::type
  91             >
  92         {};
  93
  94         base_kleene(Subject const& subject)
  95           : subject(subject) {}
  96
  97         template <
  98             typename OutputIterator, typename Context, typename Delimiter
  99           , typename Attribute>
 100         bool generate(OutputIterator& sink, Context& ctx
 101           , Delimiter const& d, Attribute const& attr) const
 102         {
 103             typedef detail::fail_function<
 104                 OutputIterator, Context, Delimiter> fail_function;
 105
 106             typedef typename traits::container_iterator<
 107                 typename add_const<Attribute>::type
 108             >::type iterator_type;
 109
 110             typedef
 111                 typename traits::make_indirect_iterator<iterator_type>::type
 112             indirect_iterator_type;
 113             typedef detail::pass_container<
 114                 fail_function, Attribute, indirect_iterator_type, mpl::false_>
 115             pass_container;
 116
 117             iterator_type it = traits::begin(attr);
 118             iterator_type end = traits::end(attr);
 119
 120             pass_container pass(fail_function(sink, ctx, d),
 121                 indirect_iterator_type(it), indirect_iterator_type(end));
 122
 123             // kleene fails only if the underlying output fails
 124             while (!pass.is_at_end())
 125             {
 126                 if (!generate_subject(pass, attr, Strict()))
 127                     break;
 128             }
 129             return detail::sink_is_good(sink);
 130         }
 131
 132         template <typename Context>
 133         info what(Context& context) const
 134         {
 135             return info("kleene", subject.what(context));
 136         }
 137
 138         Subject subject;
 139     };
 140
 141     template <typename Subject>
 142     struct kleene
 143       : base_kleene<Subject, mpl::false_, kleene<Subject> >
 144     {
 145         typedef base_kleene<Subject, mpl::false_, kleene> base_kleene_;
 146
 147         kleene(Subject const& subject)
 148           : base_kleene_(subject) {}
 149     };
 150
 151     template <typename Subject>
 152     struct strict_kleene
 153       : base_kleene<Subject, mpl::true_, strict_kleene<Subject> >
 154     {
 155         typedef base_kleene<Subject, mpl::true_, strict_kleene> base_kleene_;
 156
 157         strict_kleene(Subject const& subject)
 158           : base_kleene_(subject) {}
 159     };
 160
 161     ///////////////////////////////////////////////////////////////////////////
 162     // Generator generators: make_xxx function (objects)
 163     ///////////////////////////////////////////////////////////////////////////
 164     namespace detail
 165     {
 166         template <typename Subject, bool strict_mode = false>
 167         struct make_kleene
 168           : make_unary_composite<Subject, kleene>
 169         {};
 170
 171         template <typename Subject>
 172         struct make_kleene<Subject, true>
 173           : make_unary_composite<Subject, strict_kleene>
 174         {};
 175     }
 176
 177     template <typename Subject, typename Modifiers>
 178     struct make_composite<proto::tag::dereference, Subject, Modifiers>
 179       : detail::make_kleene<Subject, detail::get_stricttag<Modifiers>::value>
 180     {};
 181 }}}
 182
 183 namespace boost { namespace spirit { namespace traits
 184 {
 185     ///////////////////////////////////////////////////////////////////////////
 186     template <typename Subject>
 187     struct has_semantic_action<karma::kleene<Subject> >
 188       : unary_has_semantic_action<Subject> {};
 189
 190     template <typename Subject>
 191     struct has_semantic_action<karma::strict_kleene<Subject> >
 192       : unary_has_semantic_action<Subject> {};
 193
 194     ///////////////////////////////////////////////////////////////////////////
 195     template <typename Subject, typename Attribute, typename Context
 196       , typename Iterator>
 197     struct handles_container<karma::kleene<Subject>, Attribute
 198           , Context, Iterator>
 199       : mpl::true_ {};
 200
 201     template <typename Subject, typename Attribute, typename Context
 202       , typename Iterator>
 203     struct handles_container<karma::strict_kleene<Subject>, Attribute
 204           , Context, Iterator>
 205       : mpl::true_ {};
 206 }}}
 207
 208 #endif