boost/spirit/home/support/algorithm/any_if.hpp
/*=============================================================================
Copyright (c) 2001-2010 Hartmut Kaiser
Copyright (c) 2001-2010 Joel de Guzman
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(BOOST_SPIRIT_ANY_IF_MARCH_30_2007_1220PM)
#define BOOST_SPIRIT_ANY_IF_MARCH_30_2007_1220PM
#if defined(_MSC_VER)
#pragma once
#endif
#include <boost/fusion/include/equal_to.hpp>
#include <boost/fusion/include/next.hpp>
#include <boost/fusion/include/deref.hpp>
#include <boost/fusion/include/value_of.hpp>
#include <boost/fusion/include/begin.hpp>
#include <boost/fusion/include/end.hpp>
#include <boost/fusion/include/is_sequence.hpp>
#include <boost/fusion/include/any.hpp>
#include <boost/spirit/home/support/unused.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/apply.hpp>
#include <boost/mpl/if.hpp>
#include <boost/mpl/identity.hpp>
namespace boost { namespace spirit
{
///////////////////////////////////////////////////////////////////////////
// This is a special version for a binary fusion::any. The predicate
// is used to decide whether to advance the second iterator or not.
// This is needed for sequences containing components with unused
// attributes. The second iterator is advanced only if the attribute
// of the corresponding component iterator is not unused.
///////////////////////////////////////////////////////////////////////////
namespace detail
{
///////////////////////////////////////////////////////////////////////
template <typename Iterator, typename Pred>
struct apply_predicate
: mpl::apply1<Pred, typename fusion::result_of::value_of<Iterator>::type>
{};
///////////////////////////////////////////////////////////////////////
// if the predicate is true, attribute_next returns next(Iterator2),
// otherwise Iterator2
namespace result_of
{
template <typename Iterator1, typename Iterator2, typename Pred>
struct attribute_next
{
typedef typename apply_predicate<Iterator1, Pred>::type pred;
typedef typename
mpl::eval_if<
pred,
fusion::result_of::next<Iterator2>,
mpl::identity<Iterator2>
>::type
type;
template <typename Iterator>
static type
call(Iterator const& i, mpl::true_)
{
return fusion::next(i);
}
template <typename Iterator>
static type
call(Iterator const& i, mpl::false_)
{
return i;
}
template <typename Iterator>
static type
call(Iterator const& i)
{
return call(i, pred());
}
};
}
template <typename Pred, typename Iterator1, typename Iterator2>
inline typename
result_of::attribute_next<Iterator1, Iterator2, Pred
>::type const
attribute_next(Iterator2 const& i)
{
return result_of::attribute_next<Iterator1, Iterator2, Pred>::call(i);
}
///////////////////////////////////////////////////////////////////////
// if the predicate is true, attribute_value returns deref(Iterator2),
// otherwise unused
namespace result_of
{
template <typename Iterator1, typename Iterator2, typename Pred>
struct attribute_value
{
typedef typename apply_predicate<Iterator1, Pred>::type pred;
typedef typename
mpl::eval_if<
pred,
fusion::result_of::deref<Iterator2>,
mpl::identity<unused_type const>
>::type
type;
template <typename Iterator>
static type
call(Iterator const& i, mpl::true_)
{
return fusion::deref(i);
}
template <typename Iterator>
static type
call(Iterator const&, mpl::false_)
{
return unused;
}
template <typename Iterator>
static type
call(Iterator const& i)
{
return call(i, pred());
}
};
}
template <typename Pred, typename Iterator1, typename Iterator2>
inline typename
result_of::attribute_value<Iterator1, Iterator2, Pred
>::type
attribute_value(Iterator2 const& i)
{
return result_of::attribute_value<Iterator1, Iterator2, Pred>::call(i);
}
///////////////////////////////////////////////////////////////////////
template <
typename Pred, typename First1, typename Last, typename First2,
typename F
>
inline bool
any_if (First1 const&, First2 const&, Last const&, F const&, mpl::true_)
{
return false;
}
template <
typename Pred, typename First1, typename Last, typename First2,
typename F
>
inline bool
any_if (First1 const& first1, First2 const& first2, Last const& last,
F& f, mpl::false_)
{
return f(*first1, attribute_value<Pred, First1>(first2)) ||
detail::any_if<Pred>(
fusion::next(first1)
, attribute_next<Pred, First1>(first2)
, last
, f
, fusion::result_of::equal_to<
typename fusion::result_of::next<First1>::type, Last>());
}
}
template <typename Pred, typename Sequence1, typename Sequence2, typename F>
inline bool
any_if(Sequence1 const& seq1, Sequence2& seq2, F f, Pred)
{
return detail::any_if<Pred>(
fusion::begin(seq1)
, fusion::begin(seq2)
, fusion::end(seq1)
, f
, fusion::result_of::equal_to<
typename fusion::result_of::begin<Sequence1>::type
, typename fusion::result_of::end<Sequence1>::type>());
}
template <typename Pred, typename Sequence, typename F>
inline bool
any_if(Sequence const& seq, unused_type const, F f, Pred)
{
return fusion::any(seq, f);
}
}}
#endif
