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### boost/vmd/tuple/remove.hpp


//  (C) Copyright Edward Diener 2015
//  Use, modification and distribution are subject to the Boost Software License,
//  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at

#if !defined(BOOST_VMD_TUPLE_REMOVE_HPP)
#define BOOST_VMD_TUPLE_REMOVE_HPP

#include <boost/vmd/detail/setup.hpp>

#include <boost/preprocessor/comparison/equal.hpp>
#include <boost/preprocessor/control/iif.hpp>
#include <boost/preprocessor/logical/bitand.hpp>
#include <boost/preprocessor/tuple/remove.hpp>
#include <boost/preprocessor/tuple/size.hpp>
#include <boost/vmd/empty.hpp>

/*

The succeeding comments in this file are in doxygen format.

*/

/** \file
*/

/** \def BOOST_VMD_TUPLE_REMOVE(tuple,index)

\brief removes an element from a tuple.

tuple = tuple from which an element is to be removed.
index = The zero-based position in tuple of the element to be removed.

If index is greater or equal to the tuple size the result is undefined.
If the tuple is a single element and the index is 0 the result is an empty tuple.
Otherwise the result is a tuple after removing the index element.
*/

#define BOOST_VMD_TUPLE_REMOVE(tuple,index) \
BOOST_PP_IIF \
( \
BOOST_PP_BITAND \
( \
BOOST_PP_EQUAL(index,0), \
BOOST_PP_EQUAL(BOOST_PP_TUPLE_SIZE(tuple),1) \
), \
BOOST_VMD_EMPTY, \
BOOST_PP_TUPLE_REMOVE \
) \
(tuple,index) \
/**/

/** \def BOOST_VMD_TUPLE_REMOVE_D(d,tuple,index)

\brief removes an element from a tuple. It reenters BOOST_PP_WHILE with maximum efficiency.

d     = The next available BOOST_PP_WHILE iteration.
tuple = tuple from which an element is to be removed.
index = The zero-based position in tuple of the element to be removed.

If index is greater or equal to the tuple size the result is undefined.
If the tuple is a single element and the index is 0 the result is an empty tuple.
Otherwise the result is a tuple after removing the index element.
*/

#define BOOST_VMD_TUPLE_REMOVE_D(d,tuple,index) \
BOOST_PP_IIF \
( \
BOOST_PP_BITAND \
( \
BOOST_PP_EQUAL_D(d,index,0), \
BOOST_PP_EQUAL_D(d,BOOST_PP_TUPLE_SIZE(tuple),1) \
), \
BOOST_VMD_EMPTY, \
BOOST_PP_TUPLE_REMOVE_D \
) \
(d,tuple,index) \
/**/

#endif /* BOOST_PP_VARIADICS */
#endif /* BOOST_VMD_TUPLE_REMOVE_HPP */