ceph/src/boost/boost/spirit/home/karma/operator/plus.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_POSITIVE_MAR_03_2007_0945PM)
   8 #define BOOST_SPIRIT_KARMA_POSITIVE_MAR_03_2007_0945PM
   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/indirect_iterator.hpp>
  18 #include <boost/spirit/home/karma/detail/output_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/has_semantic_action.hpp>
  26 #include <boost/spirit/home/support/handles_container.hpp>
  27 #include <boost/spirit/home/karma/detail/attributes.hpp>
  28 #include <boost/proto/operators.hpp>
  29 #include <boost/proto/tags.hpp>
  30 #include <boost/type_traits/add_const.hpp>
  31
  32 namespace boost { namespace spirit
  33 {
  34     ///////////////////////////////////////////////////////////////////////////
  35     // Enablers
  36     ///////////////////////////////////////////////////////////////////////////
  37     template <>
  38     struct use_operator<karma::domain, proto::tag::unary_plus> // enables +g
  39       : mpl::true_ {};
  40 }}
  41
  42 ///////////////////////////////////////////////////////////////////////////////
  43 namespace boost { namespace spirit { namespace karma
  44 {
  45     template <typename Subject, typename Strict, typename Derived>
  46     struct base_plus : unary_generator<Derived>
  47     {
  48     private:
  49         // Ignore return value in relaxed mode (failing subject generators
  50         // are just skipped). This allows to selectively generate items in
  51         // the provided attribute.
  52         template <typename F, typename Attribute>
  53         bool generate_subject(F f, Attribute const&, bool& result, mpl::false_) const
  54         {
  55             bool r = !f(subject);
  56             if (r)
  57                 result = true;
  58             else if (!f.is_at_end())
  59                 f.next();
  60             return true;
  61         }
  62
  63         template <typename F, typename Attribute>
  64         bool generate_subject(F f, Attribute const&, bool& result, mpl::true_) const
  65         {
  66             bool r = !f(subject);
  67             if (r)
  68                 result = true;
  69             return r;
  70         }
  71
  72         // There is no way to distinguish a failed generator from a
  73         // generator to be skipped. We assume the user takes responsibility
  74         // for ending the loop if no attribute is specified.
  75         template <typename F>
  76         bool generate_subject(F f, unused_type, bool& result, mpl::false_) const
  77         {
  78             bool r = f(subject);
  79             if (!r)
  80                 result = true;
  81             return !r;
  82         }
  83
  84 //         template <typename F>
  85 //         bool generate_subject(F f, unused_type, bool& result, mpl::true_) const
  86 //         {
  87 //             bool r = f(subject);
  88 //             if (!r)
  89 //                 result = true;
  90 //             return !r;
  91 //         }
  92
  93     public:
  94         typedef Subject subject_type;
  95         typedef typename subject_type::properties properties;
  96
  97         // Build a std::vector from the subjects attribute. Note
  98         // that build_std_vector may return unused_type if the
  99         // subject's attribute is an unused_type.
 100         template <typename Context, typename Iterator>
 101         struct attribute
 102           : traits::build_std_vector<
 103                 typename traits::attribute_of<subject_type, Context, Iterator>::type
 104             >
 105         {};
 106
 107         base_plus(Subject const& subject)
 108           : subject(subject) {}
 109
 110         template <
 111             typename OutputIterator, typename Context, typename Delimiter
 112           , typename Attribute>
 113         bool generate(OutputIterator& sink, Context& ctx
 114           , Delimiter const& d, Attribute const& attr) const
 115         {
 116             typedef detail::fail_function<
 117                 OutputIterator, Context, Delimiter> fail_function;
 118
 119             typedef typename traits::container_iterator<
 120                 typename add_const<Attribute>::type
 121             >::type iterator_type;
 122
 123             typedef
 124                 typename traits::make_indirect_iterator<iterator_type>::type
 125             indirect_iterator_type;
 126             typedef detail::pass_container<
 127                 fail_function, Attribute, indirect_iterator_type, mpl::false_>
 128             pass_container;
 129
 130             iterator_type it = traits::begin(attr);
 131             iterator_type end = traits::end(attr);
 132
 133             // plus fails if the parameter is empty
 134             if (traits::compare(it, end))
 135                 return false;
 136
 137             pass_container pass(fail_function(sink, ctx, d),
 138                 indirect_iterator_type(it), indirect_iterator_type(end));
 139
 140             // from now on plus fails if the underlying output fails or overall
 141             // no subject generators succeeded
 142             bool result = false;
 143             while (!pass.is_at_end())
 144             {
 145                 if (!generate_subject(pass, attr, result, Strict()))
 146                     break;
 147             }
 148             return result && detail::sink_is_good(sink);
 149         }
 150
 151         template <typename Context>
 152         info what(Context& context) const
 153         {
 154             return info("plus", subject.what(context));
 155         }
 156
 157         Subject subject;
 158     };
 159
 160     template <typename Subject>
 161     struct plus
 162       : base_plus<Subject, mpl::false_, plus<Subject> >
 163     {
 164         typedef base_plus<Subject, mpl::false_, plus> base_plus_;
 165
 166         plus(Subject const& subject)
 167           : base_plus_(subject) {}
 168     };
 169
 170     template <typename Subject>
 171     struct strict_plus
 172       : base_plus<Subject, mpl::true_, strict_plus<Subject> >
 173     {
 174         typedef base_plus<Subject, mpl::true_, strict_plus> base_plus_;
 175
 176         strict_plus(Subject const& subject)
 177           : base_plus_(subject) {}
 178     };
 179
 180     ///////////////////////////////////////////////////////////////////////////
 181     // Generator generators: make_xxx function (objects)
 182     ///////////////////////////////////////////////////////////////////////////
 183     namespace detail
 184     {
 185         template <typename Elements, bool strict_mode = false>
 186         struct make_plus
 187           : make_unary_composite<Elements, plus>
 188         {};
 189
 190         template <typename Elements>
 191         struct make_plus<Elements, true>
 192           : make_unary_composite<Elements, strict_plus>
 193         {};
 194     }
 195
 196     template <typename Elements, typename Modifiers>
 197     struct make_composite<proto::tag::unary_plus, Elements, Modifiers>
 198       : detail::make_plus<Elements, detail::get_stricttag<Modifiers>::value>
 199     {};
 200 }}}
 201
 202 namespace boost { namespace spirit { namespace traits
 203 {
 204     ///////////////////////////////////////////////////////////////////////////
 205     template <typename Subject>
 206     struct has_semantic_action<karma::plus<Subject> >
 207       : unary_has_semantic_action<Subject> {};
 208
 209     template <typename Subject>
 210     struct has_semantic_action<karma::strict_plus<Subject> >
 211       : unary_has_semantic_action<Subject> {};
 212
 213     ///////////////////////////////////////////////////////////////////////////
 214     template <typename Subject, typename Attribute, typename Context
 215       , typename Iterator>
 216     struct handles_container<karma::plus<Subject>, Attribute
 217           , Context, Iterator>
 218       : mpl::true_ {};
 219
 220     template <typename Subject, typename Attribute, typename Context
 221       , typename Iterator>
 222     struct handles_container<karma::strict_plus<Subject>, Attribute
 223           , Context, Iterator>
 224       : mpl::true_ {};
 225 }}}
 226
 227 #endif