ceph/src/boost/boost/spirit/home/karma/directive/as.hpp

   1 //  Copyright (c) 2001-2011 Hartmut Kaiser
   2 //  Copyright (c)      2010 Bryce Lelbach
   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 #ifndef BOOST_SPIRIT_KARMA_DIRECTIVE_AS_HPP
   8 #define BOOST_SPIRIT_KARMA_DIRECTIVE_AS_HPP
   9
  10 #if defined(_MSC_VER)
  11 #pragma once
  12 #endif
  13
  14 #include <boost/spirit/home/karma/meta_compiler.hpp>
  15 #include <boost/spirit/home/karma/generator.hpp>
  16 #include <boost/spirit/home/karma/delimit_out.hpp>
  17 #include <boost/spirit/home/karma/domain.hpp>
  18 #include <boost/spirit/home/karma/detail/output_iterator.hpp>
  19 #include <boost/spirit/home/karma/detail/as.hpp>
  20 #include <boost/spirit/home/support/unused.hpp>
  21 #include <boost/spirit/home/support/info.hpp>
  22 #include <boost/spirit/home/support/common_terminals.hpp>
  23 #include <boost/spirit/home/support/has_semantic_action.hpp>
  24 #include <boost/spirit/home/support/handles_container.hpp>
  25 #include <boost/spirit/home/support/assert_msg.hpp>
  26 #include <boost/spirit/home/support/container.hpp>
  27 #include <boost/spirit/home/karma/detail/attributes.hpp>
  28
  29 namespace boost { namespace spirit { namespace karma
  30 {
  31     template <typename T>
  32     struct as
  33       : stateful_tag_type<T, tag::as>
  34     {
  35         BOOST_SPIRIT_ASSERT_MSG(
  36             (traits::is_container<T>::type::value),
  37             error_type_must_be_a_container,
  38             (T));
  39     };
  40 }}}
  41
  42 namespace boost { namespace spirit
  43 {
  44     ///////////////////////////////////////////////////////////////////////////
  45     // Enablers
  46     ///////////////////////////////////////////////////////////////////////////
  47     // enables as_string[...]
  48     template <>
  49     struct use_directive<karma::domain, tag::as_string>
  50       : mpl::true_ {};
  51
  52     // enables as_wstring[...]
  53     template <>
  54     struct use_directive<karma::domain, tag::as_wstring>
  55       : mpl::true_ {};
  56
  57     // enables as<T>[...]
  58     template <typename T>
  59     struct use_directive<karma::domain, tag::stateful_tag<T, tag::as> >
  60       : mpl::true_
  61     {};
  62 }}
  63
  64 namespace boost { namespace spirit { namespace karma
  65 {
  66 #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
  67     using spirit::as_string;
  68     using spirit::as_wstring;
  69 #endif
  70     using spirit::as_string_type;
  71     using spirit::as_wstring_type;
  72
  73     ///////////////////////////////////////////////////////////////////////////
  74     // as_directive allows to hook custom conversions to string into the
  75     // output generation process
  76     ///////////////////////////////////////////////////////////////////////////
  77     template <typename Subject, typename T>
  78     struct as_directive
  79       : unary_generator<as_directive<Subject, T> >
  80     {
  81         typedef Subject subject_type;
  82         typedef typename subject_type::properties properties;
  83
  84         as_directive(Subject const& subject)
  85           : subject(subject) {}
  86
  87         template <typename Context, typename Iterator>
  88         struct attribute
  89         {
  90             typedef T type;
  91         };
  92
  93         template <typename OutputIterator, typename Context, typename Delimiter
  94           , typename Attribute>
  95         bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
  96           , Attribute const& attr) const
  97         {
  98             if (!traits::valid_as<T>(attr))
  99                 return false;
 100
 101             return subject.generate(sink, ctx, d, traits::as<T>(attr)) &&
 102                     karma::delimit_out(sink, d); // always do post-delimiting
 103         }
 104
 105         template <typename Context>
 106         info what(Context& context) const
 107         {
 108             return info("as", subject.what(context));
 109         }
 110
 111         Subject subject;
 112     };
 113
 114     ///////////////////////////////////////////////////////////////////////////
 115     // Generator generators: make_xxx function (objects)
 116     ///////////////////////////////////////////////////////////////////////////
 117     template <typename Subject, typename Modifiers>
 118     struct make_directive<tag::as_string, Subject, Modifiers>
 119     {
 120         typedef as_directive<Subject, std::string> result_type;
 121         result_type operator()(unused_type, Subject const& subject
 122           , unused_type) const
 123         {
 124             return result_type(subject);
 125         }
 126     };
 127
 128     template <typename Subject, typename Modifiers>
 129     struct make_directive<tag::as_wstring, Subject, Modifiers>
 130     {
 131         typedef as_directive<Subject, std::basic_string<wchar_t> > result_type;
 132         result_type operator()(unused_type, Subject const& subject
 133           , unused_type) const
 134         {
 135             return result_type(subject);
 136         }
 137     };
 138
 139     template <typename T, typename Subject, typename Modifiers>
 140     struct make_directive<tag::stateful_tag<T, tag::as>, Subject, Modifiers>
 141     {
 142         typedef as_directive<Subject, T> result_type;
 143         result_type operator()(unused_type, Subject const& subject
 144           , unused_type) const
 145         {
 146             return result_type(subject);
 147         }
 148     };
 149 }}}
 150
 151 namespace boost { namespace spirit { namespace traits
 152 {
 153     ///////////////////////////////////////////////////////////////////////////
 154     template <typename Subject, typename T>
 155     struct has_semantic_action<karma::as_directive<Subject, T> >
 156       : unary_has_semantic_action<Subject> {};
 157
 158     ///////////////////////////////////////////////////////////////////////////
 159     template <typename Subject, typename T, typename Attribute
 160       , typename Context, typename Iterator>
 161     struct handles_container<karma::as_directive<Subject, T>, Attribute
 162       , Context, Iterator>
 163       : mpl::false_ {};   // always dereference attribute if used in sequences
 164 }}}
 165
 166 #endif