ecency-mobile/ios/Pods/boost-for-react-native/boost/vmd/tuple/push_front.hpp

54 lines
1.4 KiB
C++

// (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
// http://www.boost.org/LICENSE_1_0.txt).
#if !defined(BOOST_VMD_TUPLE_PUSH_FRONT_HPP)
#define BOOST_VMD_TUPLE_PUSH_FRONT_HPP
#include <boost/vmd/detail/setup.hpp>
#if BOOST_PP_VARIADICS
#include <boost/preprocessor/control/iif.hpp>
#include <boost/preprocessor/tuple/push_front.hpp>
#include <boost/vmd/identity.hpp>
#include <boost/vmd/is_empty.hpp>
/*
The succeeding comments in this file are in doxygen format.
*/
/** \file
*/
/** \def BOOST_VMD_TUPLE_PUSH_FRONT(tuple,elem)
\brief inserts an element at the beginning of a tuple.
tuple = tuple to insert an element at.
elem = element to insert.
If the tuple is an empty tuple the result is a tuple with the single element.
Otherwise the result is a tuple after inserting the element at the beginning.
*/
#define BOOST_VMD_TUPLE_PUSH_FRONT(tuple,elem) \
BOOST_VMD_IDENTITY_RESULT \
( \
BOOST_PP_IIF \
( \
BOOST_VMD_IS_EMPTY(tuple), \
BOOST_VMD_IDENTITY((elem)), \
BOOST_PP_TUPLE_PUSH_FRONT \
) \
(tuple,elem) \
) \
/**/
#endif /* BOOST_PP_VARIADICS */
#endif /* BOOST_VMD_TUPLE_PUSH_FRONT_HPP */