vmd/tuple/pop_front.hpp

0001
0002 //  (C) Copyright Edward Diener 2015
0003 //  Use, modification and distribution are subject to the Boost Software License,
0004 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0005 //  http://www.boost.org/LICENSE_1_0.txt).
0006
0007 #if !defined(BOOST_VMD_TUPLE_POP_FRONT_HPP)
0008 #define BOOST_VMD_TUPLE_POP_FRONT_HPP
0009
0010 #include <boost/vmd/detail/setup.hpp>
0011
0012 #if BOOST_PP_VARIADICS
0013
0014 #include <boost/preprocessor/comparison/equal.hpp>
0015 #include <boost/preprocessor/control/iif.hpp>
0016 #include <boost/preprocessor/tuple/pop_front.hpp>
0017 #include <boost/preprocessor/tuple/size.hpp>
0018 #include <boost/vmd/empty.hpp>
0019
0020 /*
0021
0022   The succeeding comments in this file are in doxygen format.
0023
0024 */
0025
0026 /** \file
0027 */
0028
0029 /** \def BOOST_VMD_TUPLE_POP_FRONT(tuple)
0030
0031     \brief pops an element from the front of a tuple.
0032
0033     tuple = tuple to pop an element from.
0034
0035     If the tuple is an empty tuple the result is undefined.
0036     If the tuple is a single element the result is an empty tuple.
0037     Otherwise the result is a tuple after removing the first element.
0038 */
0039
0040 #define BOOST_VMD_TUPLE_POP_FRONT(tuple) \
0041     BOOST_PP_IIF \
0042         ( \
0043         BOOST_PP_EQUAL(BOOST_PP_TUPLE_SIZE(tuple),1), \
0044         BOOST_VMD_EMPTY, \
0045         BOOST_PP_TUPLE_POP_FRONT \
0046         ) \
0047     (tuple) \
0048 /**/
0049
0050 /** \def BOOST_VMD_TUPLE_POP_FRONT_Z(z,tuple)
0051
0052     \brief pops an element from the front of a tuple. It reenters BOOST_PP_REPEAT with maximum efficiency.
0053
0054     z     = the next available BOOST_PP_REPEAT dimension. <br/>
0055     tuple = tuple to pop an element from.
0056
0057     If the tuple is an empty tuple the result is undefined.
0058     If the tuple is a single element the result is an empty tuple.
0059     Otherwise the result is a tuple after removing the first element.
0060 */
0061
0062 #define BOOST_VMD_TUPLE_POP_FRONT_Z(z,tuple) \
0063     BOOST_PP_IIF \
0064         ( \
0065         BOOST_PP_EQUAL(BOOST_PP_TUPLE_SIZE(tuple),1), \
0066         BOOST_VMD_EMPTY, \
0067         BOOST_PP_TUPLE_POP_FRONT_Z \
0068         ) \
0069     (z,tuple) \
0070 /**/
0071
0072 #endif /* BOOST_PP_VARIADICS */
0073 #endif /* BOOST_VMD_TUPLE_POP_FRONT_HPP */