ceph/src/boost/libs/spirit/include/boost/spirit/home/karma/auxiliary/attr_cast.hpp

   1 //  Copyright (c) 2001-2011 Hartmut Kaiser
   2 //
   3 //  Distributed under the Boost Software License, Version 1.0. (See accompanying
   4 //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #if !defined(SPIRIT_KARMA_ATTR_CAST_SEP_26_2009_0348PM)
   7 #define SPIRIT_KARMA_ATTR_CAST_SEP_26_2009_0348PM
   8
   9 #if defined(_MSC_VER)
  10 #pragma once
  11 #endif
  12
  13 #include <boost/spirit/home/karma/meta_compiler.hpp>
  14 #include <boost/spirit/home/karma/generator.hpp>
  15 #include <boost/spirit/home/karma/domain.hpp>
  16 #include <boost/spirit/home/support/unused.hpp>
  17 #include <boost/spirit/home/support/info.hpp>
  18 #include <boost/spirit/home/support/common_terminals.hpp>
  19 #include <boost/spirit/home/karma/detail/attributes.hpp>
  20 #include <boost/spirit/home/support/auxiliary/attr_cast.hpp>
  21
  22 namespace boost { namespace spirit
  23 {
  24     ///////////////////////////////////////////////////////////////////////////
  25     // enables attr_cast<>() pseudo generator
  26     template <typename Expr, typename Exposed, typename Transformed>
  27     struct use_terminal<karma::domain
  28           , tag::stateful_tag<Expr, tag::attr_cast, Exposed, Transformed> >
  29       : mpl::true_ {};
  30 }}
  31
  32 namespace boost { namespace spirit { namespace karma
  33 {
  34 #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
  35     using spirit::attr_cast;
  36 #endif
  37
  38     ///////////////////////////////////////////////////////////////////////////
  39     // attr_cast_generator consumes the attribute of subject generator without
  40     // generating anything
  41     ///////////////////////////////////////////////////////////////////////////
  42     template <typename Exposed, typename Transformed, typename Subject>
  43     struct attr_cast_generator
  44       : unary_generator<attr_cast_generator<Exposed, Transformed, Subject> >
  45     {
  46         typedef typename result_of::compile<karma::domain, Subject>::type
  47             subject_type;
  48
  49         typedef mpl::int_<subject_type::properties::value> properties;
  50
  51         typedef typename mpl::eval_if<
  52             traits::not_is_unused<Transformed>
  53           , mpl::identity<Transformed>
  54           , traits::attribute_of<subject_type> >::type
  55         transformed_attribute_type;
  56
  57         attr_cast_generator(Subject const& subject)
  58           : subject(subject)
  59         {
  60             // If you got an error_invalid_expression error message here,
  61             // then the expression (Subject) is not a valid spirit karma
  62             // expression.
  63             BOOST_SPIRIT_ASSERT_MATCH(karma::domain, Subject);
  64         }
  65
  66         // If Exposed is given, we use the given type, otherwise all we can do
  67         // is to guess, so we expose our inner type as an attribute and
  68         // deal with the passed attribute inside the parse function.
  69         template <typename Context, typename Unused>
  70         struct attribute
  71           : mpl::if_<traits::not_is_unused<Exposed>, Exposed
  72               , transformed_attribute_type>
  73         {};
  74
  75         template <typename OutputIterator, typename Context, typename Delimiter
  76           , typename Attribute>
  77         bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
  78           , Attribute const& attr) const
  79         {
  80             typedef traits::transform_attribute<
  81                 Attribute const, transformed_attribute_type, domain>
  82             transform;
  83
  84             return compile<karma::domain>(subject).generate(
  85                 sink, ctx, d, transform::pre(attr));
  86         }
  87
  88         template <typename Context>
  89         info what(Context& context) const
  90         {
  91             return info("attr_cast"
  92               , compile<karma::domain>(subject).what(context));
  93         }
  94
  95         Subject subject;
  96     };
  97
  98     ///////////////////////////////////////////////////////////////////////////
  99     // Generator generator: make_xxx function (objects)
 100     ///////////////////////////////////////////////////////////////////////////
 101     template <typename Expr, typename Exposed, typename Transformed
 102       , typename Modifiers>
 103     struct make_primitive<
 104         tag::stateful_tag<Expr, tag::attr_cast, Exposed, Transformed>, Modifiers>
 105     {
 106         typedef attr_cast_generator<Exposed, Transformed, Expr> result_type;
 107
 108         template <typename Terminal>
 109         result_type operator()(Terminal const& term, unused_type) const
 110         {
 111             typedef tag::stateful_tag<
 112                 Expr, tag::attr_cast, Exposed, Transformed> tag_type;
 113             using spirit::detail::get_stateful_data;
 114             return result_type(get_stateful_data<tag_type>::call(term));
 115         }
 116     };
 117
 118 }}}
 119
 120 #endif