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 #if !defined(SPIRIT_KARMA_AS_DEC_18_0510PM)
   8 #define SPIRIT_KARMA_AS_DEC_18_0510PM
   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/domain.hpp>
  17 #include <boost/spirit/home/karma/detail/output_iterator.hpp>
  18 #include <boost/spirit/home/karma/detail/as.hpp>
  19 #include <boost/spirit/home/support/unused.hpp>
  20 #include <boost/spirit/home/support/info.hpp>
  21 #include <boost/spirit/home/support/common_terminals.hpp>
  22 #include <boost/spirit/home/support/has_semantic_action.hpp>
  23 #include <boost/spirit/home/support/handles_container.hpp>
  24 #include <boost/spirit/home/support/assert_msg.hpp>
  25 #include <boost/spirit/home/support/container.hpp>
  26 #include <boost/spirit/home/karma/detail/attributes.hpp>
  27
  28 namespace boost { namespace spirit { namespace karma
  29 {
  30     template <typename T>
  31     struct as
  32       : stateful_tag_type<T, tag::as>
  33     {
  34         BOOST_SPIRIT_ASSERT_MSG(
  35             (traits::is_container<T>::type::value),
  36             error_type_must_be_a_container,
  37             (T));
  38     };
  39 }}}
  40
  41 namespace boost { namespace spirit
  42 {
  43     ///////////////////////////////////////////////////////////////////////////
  44     // Enablers
  45     ///////////////////////////////////////////////////////////////////////////
  46     // enables as_string[...]
  47     template <>
  48     struct use_directive<karma::domain, tag::as_string>
  49       : mpl::true_ {};
  50
  51     // enables as_wstring[...]
  52     template <>
  53     struct use_directive<karma::domain, tag::as_wstring>
  54       : mpl::true_ {};
  55
  56     // enables as<T>[...]
  57     template <typename T>
  58     struct use_directive<karma::domain, tag::stateful_tag<T, tag::as> >
  59       : mpl::true_
  60     {};
  61 }}
  62
  63 namespace boost { namespace spirit { namespace karma
  64 {
  65 #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
  66     using spirit::as_string;
  67     using spirit::as_wstring;
  68 #endif
  69     using spirit::as_string_type;
  70     using spirit::as_wstring_type;
  71
  72     ///////////////////////////////////////////////////////////////////////////
  73     // as_directive allows to hook custom conversions to string into the
  74     // output generation process
  75     ///////////////////////////////////////////////////////////////////////////
  76     template <typename Subject, typename T>
  77     struct as_directive
  78       : unary_generator<as_directive<Subject, T> >
  79     {
  80         typedef Subject subject_type;
  81         typedef typename subject_type::properties properties;
  82
  83         as_directive(Subject const& subject)
  84           : subject(subject) {}
  85
  86         template <typename Context, typename Iterator>
  87         struct attribute
  88         {
  89             typedef T type;
  90         };
  91
  92         template <typename OutputIterator, typename Context, typename Delimiter
  93           , typename Attribute>
  94         bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
  95           , Attribute const& attr) const
  96         {
  97             if (!traits::valid_as<T>(attr))
  98                 return false;
  99
 100             return subject.generate(sink, ctx, d, traits::as<T>(attr)) &&
 101                     karma::delimit_out(sink, d); // always do post-delimiting
 102         }
 103
 104         template <typename Context>
 105         info what(Context& context) const
 106         {
 107             return info("as", subject.what(context));
 108         }
 109
 110         Subject subject;
 111     };
 112
 113     ///////////////////////////////////////////////////////////////////////////
 114     // Generator generators: make_xxx function (objects)
 115     ///////////////////////////////////////////////////////////////////////////
 116     template <typename Subject, typename Modifiers>
 117     struct make_directive<tag::as_string, Subject, Modifiers>
 118     {
 119         typedef as_directive<Subject, std::string> result_type;
 120         result_type operator()(unused_type, Subject const& subject
 121           , unused_type) const
 122         {
 123             return result_type(subject);
 124         }
 125     };
 126
 127     template <typename Subject, typename Modifiers>
 128     struct make_directive<tag::as_wstring, Subject, Modifiers>
 129     {
 130         typedef as_directive<Subject, std::basic_string<wchar_t> > result_type;
 131         result_type operator()(unused_type, Subject const& subject
 132           , unused_type) const
 133         {
 134             return result_type(subject);
 135         }
 136     };
 137
 138     template <typename T, typename Subject, typename Modifiers>
 139     struct make_directive<tag::stateful_tag<T, tag::as>, Subject, Modifiers>
 140     {
 141         typedef as_directive<Subject, T> result_type;
 142         result_type operator()(unused_type, Subject const& subject
 143           , unused_type) const
 144         {
 145             return result_type(subject);
 146         }
 147     };
 148 }}}
 149
 150 namespace boost { namespace spirit { namespace traits
 151 {
 152     ///////////////////////////////////////////////////////////////////////////
 153     template <typename Subject, typename T>
 154     struct has_semantic_action<karma::as_directive<Subject, T> >
 155       : unary_has_semantic_action<Subject> {};
 156
 157     ///////////////////////////////////////////////////////////////////////////
 158     template <typename Subject, typename T, typename Attribute
 159       , typename Context, typename Iterator>
 160     struct handles_container<karma::as_directive<Subject, T>, Attribute
 161       , Context, Iterator>
 162       : mpl::false_ {};   // always dereference attribute if used in sequences
 163 }}}
 164
 165 #endif