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