third_party/boost/include/boost/wave/util/transform_iterator.hpp

/*=============================================================================
    Boost.Wave: A Standard compliant C++ preprocessor library

    http://www.boost.org/

    Copyright (c) 2001-2011 Hartmut Kaiser. Distributed under the Boost
    Software License, Version 1.0. (See accompanying file
    LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/

#if !defined(TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED)
#define TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED

#include <boost/config.hpp>
#include <boost/iterator_adaptors.hpp>
#include <boost/iterator/transform_iterator.hpp>

#include <boost/assert.hpp>

// this must occur after all of the includes and before any code appears
#ifdef BOOST_HAS_ABI_HEADERS
#include BOOST_ABI_PREFIX
#endif

///////////////////////////////////////////////////////////////////////////////
namespace boost {
namespace wave { 
namespace impl {

///////////////////////////////////////////////////////////////////////////////
//
//  The new Boost.Iterator library already conatins a transform_iterator usable 
//  for our needs. The code below wraps this up.
//
///////////////////////////////////////////////////////////////////////////////
    template <class AdaptableUnaryFunctionT, class IteratorT>
    class ref_transform_iterator_generator
    {
        typedef typename AdaptableUnaryFunctionT::result_type   return_type;
        typedef typename AdaptableUnaryFunctionT::argument_type argument_type;

    public:
        typedef boost::transform_iterator<
                return_type (*)(argument_type), IteratorT, return_type>
            type;
    };

    template <class AdaptableUnaryFunctionT, class IteratorT>
    inline 
    typename ref_transform_iterator_generator<
        AdaptableUnaryFunctionT, IteratorT>::type
    make_ref_transform_iterator(
        IteratorT base, AdaptableUnaryFunctionT const &f)
    {
        typedef typename ref_transform_iterator_generator<
                AdaptableUnaryFunctionT, IteratorT>::type
            iterator_type;
        return iterator_type(base, f.transform);
    }

    //  Retrieve the token value given a parse node
    //  This is used in conjunction with the ref_transform_iterator above, to
    //  get the token values while iterating directly over the parse tree.
    template <typename TokenT, typename ParseTreeNodeT>
    struct get_token_value {

        typedef TokenT const &result_type;
        typedef ParseTreeNodeT const &argument_type;

        static result_type
        transform (argument_type node) 
        {
            BOOST_ASSERT(1 == std::distance(node.value.begin(), 
                node.value.end()));
            return *node.value.begin();
        }
    };

///////////////////////////////////////////////////////////////////////////////
}   // namespace impl
}   // namespace wave
}   // namespace boost

// the suffix header occurs after all of the code
#ifdef BOOST_HAS_ABI_HEADERS
#include BOOST_ABI_SUFFIX
#endif

#endif // !defined(TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED)