/*=============================================================================
Wave: A Standard compliant C++ preprocessor
Copyright (c) 2001-2003 Hartmut Kaiser
http://spirit.sourceforge.net/
Permission to copy, use, modify, sell and distribute this software
is granted provided this copyright notice appears in all copies.
This software is provided "as is" without express or implied
warranty, and with no claim as to its suitability for any purpose.
See Copyright.txt for full copyright notices and acknowledgements.
=============================================================================*/
#if !defined(TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED)
#define TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED
#include <boost/iterator_adaptors.hpp>
#include <boost/spirit/core/assert.hpp>
///////////////////////////////////////////////////////////////////////////////
namespace wave {
namespace impl {
///////////////////////////////////////////////////////////////////////////////
//
// Transform Iterator Adaptor
//
// Upon deference, apply some unary function object and return the
// result by reference.
//
// This class is adapted from the Boost.Iterator library, where a similar
// class exists, which returns the next item by value
template <class AdaptableUnaryFunctionT>
struct ref_transform_iterator_policies
: public boost::default_iterator_policies
{
ref_transform_iterator_policies()
{}
ref_transform_iterator_policies(const AdaptableUnaryFunctionT &f)
: m_f(f) {}
template <class IteratorAdaptorT>
typename IteratorAdaptorT::reference
dereference(const IteratorAdaptorT &iter) const
{ return m_f(*iter.base()); }
AdaptableUnaryFunctionT m_f;
};
template <class AdaptableUnaryFunctionT, class IteratorT>
class ref_transform_iterator_generator
{
typedef typename AdaptableUnaryFunctionT::result_type value_type;
public:
typedef boost::iterator_adaptor<
IteratorT,
ref_transform_iterator_policies<AdaptableUnaryFunctionT>,
value_type, value_type const &, value_type const *,
std::input_iterator_tag>
type;
};
template <class AdaptableUnaryFunctionT, class IteratorT>
inline
typename ref_transform_iterator_generator<
AdaptableUnaryFunctionT, IteratorT>::type
make_ref_transform_iterator(
IteratorT base,
const AdaptableUnaryFunctionT &f = AdaptableUnaryFunctionT())
{
typedef typename ref_transform_iterator_generator<
AdaptableUnaryFunctionT, IteratorT>::type
result_t;
return result_t(base, f);
}
// Retrieve the token value given a parse node
// This is used in conjunctione 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 result_type;
TokenT const &operator()(ParseTreeNodeT const &node) const
{
BOOST_SPIRIT_ASSERT(1 == std::distance(node.value.begin(),
node.value.end()));
return *node.value.begin();
}
};
///////////////////////////////////////////////////////////////////////////////
} // namespace impl
} // namespace wave
#endif // !defined(TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED)