1 
2 #ifndef BOOST_MPL_AUX_PREPROCESSOR_TOKEN_EQUAL_HPP_INCLUDED
3 #define BOOST_MPL_AUX_PREPROCESSOR_TOKEN_EQUAL_HPP_INCLUDED
4 
5 // Copyright Paul Mensonides 2003
6 // Copyright Aleksey Gurtovoy 2003-2004
7 //
8 // Distributed under the Boost Software License, Version 1.0.
9 // (See accompanying file LICENSE_1_0.txt or copy at
10 // http://www.boost.org/LICENSE_1_0.txt)
11 //
12 // See http://www.boost.org/libs/mpl for documentation.
13 
14 // $Id$
15 // $Date$
16 // $Revision$
17 
18 #include <boost/mpl/aux_/preprocessor/is_seq.hpp>
19 
20 #include <boost/preprocessor/if.hpp>
21 #include <boost/preprocessor/logical/bitand.hpp>
22 #include <boost/preprocessor/logical/compl.hpp>
23 #include <boost/preprocessor/tuple/eat.hpp>
24 #include <boost/preprocessor/cat.hpp>
25 
26 // compares tokens 'a' and 'b' for equality:
27 //
28 //   #define BOOST_MPL_PP_TOKEN_EQUAL_apple(x) x
29 //   #define BOOST_MPL_PP_TOKEN_EQUAL_orange(x) x
30 //
31 //   BOOST_PP_ASSERT( BOOST_PP_NOT( BOOST_MPL_PP_TOKEN_EQUAL(apple, abc) ) )
32 //   BOOST_PP_ASSERT( BOOST_PP_NOT( BOOST_MPL_PP_TOKEN_EQUAL(abc, apple) ) )
33 //   BOOST_PP_ASSERT( BOOST_PP_NOT( BOOST_MPL_PP_TOKEN_EQUAL(apple, orange) ) )
34 //   BOOST_PP_ASSERT( BOOST_MPL_PP_TOKEN_EQUAL(apple, apple) )
35 //   BOOST_PP_ASSERT( BOOST_MPL_PP_TOKEN_EQUAL(orange, orange) )
36 
37 #define BOOST_MPL_PP_TOKEN_EQUAL(a, b) \
38     BOOST_PP_IIF( \
39         BOOST_PP_BITAND( \
40               BOOST_MPL_PP_IS_SEQ( BOOST_PP_CAT(BOOST_MPL_PP_TOKEN_EQUAL_, a)((unused)) ) \
41             , BOOST_MPL_PP_IS_SEQ( BOOST_PP_CAT(BOOST_MPL_PP_TOKEN_EQUAL_, b)((unused)) ) \
42             ) \
43         , BOOST_MPL_PP_TOKEN_EQUAL_I \
44         , 0 BOOST_PP_TUPLE_EAT(2) \
45         )(a, b) \
46 /**/
47 
48 #define BOOST_MPL_PP_TOKEN_EQUAL_I(a, b) \
49     BOOST_PP_COMPL(BOOST_MPL_PP_IS_SEQ( \
50         BOOST_MPL_PP_TOKEN_EQUAL_ ## a( \
51             BOOST_MPL_PP_TOKEN_EQUAL_ ## b \
52             )((unused)) \
53         )) \
54 /**/
55 
56 #endif // BOOST_MPL_AUX_PREPROCESSOR_TOKEN_EQUAL_HPP_INCLUDED
57