Chris@16: //  Copyright (c) 2001-2011 Hartmut Kaiser
Chris@16: //
Chris@16: //  Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #if !defined(SPIRIT_KARMA_ATTR_CAST_SEP_26_2009_0348PM)
Chris@16: #define SPIRIT_KARMA_ATTR_CAST_SEP_26_2009_0348PM
Chris@16: 
Chris@16: #if defined(_MSC_VER)
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/spirit/home/karma/meta_compiler.hpp>
Chris@16: #include <boost/spirit/home/karma/generator.hpp>
Chris@16: #include <boost/spirit/home/karma/domain.hpp>
Chris@16: #include <boost/spirit/home/support/unused.hpp>
Chris@16: #include <boost/spirit/home/support/info.hpp>
Chris@16: #include <boost/spirit/home/support/common_terminals.hpp>
Chris@16: #include <boost/spirit/home/karma/detail/attributes.hpp>
Chris@16: #include <boost/spirit/home/support/auxiliary/attr_cast.hpp>
Chris@16: 
Chris@16: namespace boost { namespace spirit
Chris@16: {
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // enables attr_cast<>() pseudo generator
Chris@16:     template <typename Expr, typename Exposed, typename Transformed>
Chris@16:     struct use_terminal<karma::domain
Chris@16:           , tag::stateful_tag<Expr, tag::attr_cast, Exposed, Transformed> >
Chris@16:       : mpl::true_ {};
Chris@16: }}
Chris@16: 
Chris@16: namespace boost { namespace spirit { namespace karma
Chris@16: {
Chris@16: #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
Chris@16:     using spirit::attr_cast;
Chris@16: #endif
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // attr_cast_generator consumes the attribute of subject generator without
Chris@16:     // generating anything
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Exposed, typename Transformed, typename Subject>
Chris@16:     struct attr_cast_generator
Chris@16:       : unary_generator<attr_cast_generator<Exposed, Transformed, Subject> >
Chris@16:     {
Chris@16:         typedef typename result_of::compile<karma::domain, Subject>::type
Chris@16:             subject_type;
Chris@16: 
Chris@16:         typedef mpl::int_<subject_type::properties::value> properties;
Chris@16: 
Chris@16:         typedef typename mpl::eval_if<
Chris@16:             traits::not_is_unused<Transformed>
Chris@16:           , mpl::identity<Transformed>
Chris@16:           , traits::attribute_of<subject_type> >::type 
Chris@16:         transformed_attribute_type;
Chris@16: 
Chris@16:         attr_cast_generator(Subject const& subject)
Chris@16:           : subject(subject) 
Chris@16:         {
Chris@16:             // If you got an error_invalid_expression error message here,
Chris@16:             // then the expression (Subject) is not a valid spirit karma
Chris@16:             // expression.
Chris@16:             BOOST_SPIRIT_ASSERT_MATCH(karma::domain, Subject);
Chris@16:         }
Chris@16: 
Chris@16:         // If Exposed is given, we use the given type, otherwise all we can do
Chris@16:         // is to guess, so we expose our inner type as an attribute and
Chris@16:         // deal with the passed attribute inside the parse function.
Chris@16:         template <typename Context, typename Unused>
Chris@16:         struct attribute
Chris@16:           : mpl::if_<traits::not_is_unused<Exposed>, Exposed
Chris@16:               , transformed_attribute_type>
Chris@16:         {};
Chris@16: 
Chris@16:         template <typename OutputIterator, typename Context, typename Delimiter
Chris@16:           , typename Attribute>
Chris@16:         bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
Chris@16:           , Attribute const& attr) const
Chris@16:         {
Chris@16:             typedef traits::transform_attribute<
Chris@16:                 Attribute const, transformed_attribute_type, domain> 
Chris@16:             transform;
Chris@16: 
Chris@16:             return compile<karma::domain>(subject).generate(
Chris@16:                 sink, ctx, d, transform::pre(attr));
Chris@16:         }
Chris@16: 
Chris@16:         template <typename Context>
Chris@16:         info what(Context& context) const
Chris@16:         {
Chris@16:             return info("attr_cast"
Chris@16:               , compile<karma::domain>(subject).what(context));
Chris@16:         }
Chris@16: 
Chris@16:         Subject subject;
Chris@16:     };
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // Generator generator: make_xxx function (objects)
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Expr, typename Exposed, typename Transformed
Chris@16:       , typename Modifiers>
Chris@16:     struct make_primitive<
Chris@16:         tag::stateful_tag<Expr, tag::attr_cast, Exposed, Transformed>, Modifiers>
Chris@16:     {
Chris@16:         typedef attr_cast_generator<Exposed, Transformed, Expr> result_type;
Chris@16: 
Chris@16:         template <typename Terminal>
Chris@16:         result_type operator()(Terminal const& term, unused_type) const
Chris@16:         {
Chris@16:             typedef tag::stateful_tag<
Chris@16:                 Expr, tag::attr_cast, Exposed, Transformed> tag_type;
Chris@16:             using spirit::detail::get_stateful_data;
Chris@16:             return result_type(get_stateful_data<tag_type>::call(term));
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16: }}}
Chris@16: 
Chris@16: #endif