Re: [Boost-bugs] [Boost C++ Libraries] #12426: boost/preprocessor/seq/for_each_i.hpp fails on gcc 5.4.0 and appleclang 7.3.0

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #12426: boost/preprocessor/seq/for_each_i.hpp fails on gcc 5.4.0 and appleclang 7.3.0
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-09-20 21:38:07

#12426: boost/preprocessor/seq/for_each_i.hpp fails on gcc 5.4.0 and appleclang
7.3.0
-------------------------------+---------------------------
  Reporter:  mjtruog@…         |      Owner:  no-maintainer
      Type:  Bugs              |     Status:  new
 Milestone:  To Be Determined  |  Component:  preprocessor
   Version:  Boost 1.58.0      |   Severity:  Problem
Resolution:                    |   Keywords:
-------------------------------+---------------------------

Comment (by mjtruog@…):

 The diff below solves the problem, by bringing the code for the arity 0
 case back to the state it was in at version 1.48 (when compared to 1.58):
 {{{
 --- /usr/include/boost/preprocessor/tuple/to_seq.hpp    2016-09-20
 13:34:52.926120462 -0700
 +++ /usr/include/boost/preprocessor/tuple/to_seq.hpp        2016-09-20
 13:35:02.516377864 -0700
 @@ -49,7 +49,7 @@
  # endif
  #
  /* An empty array can be passed */
 -# define BOOST_PP_TUPLE_TO_SEQ_0() ()
 +# define BOOST_PP_TUPLE_TO_SEQ_0()
  #
  # define BOOST_PP_TUPLE_TO_SEQ_1(e0) (e0)
  # define BOOST_PP_TUPLE_TO_SEQ_2(e0, e1) (e0)(e1)
 }}}

 To avoid this bug in BOOST_PP_TUPLE_TO_SEQ I used the work-around below:
 {{{
 #include <boost/preprocessor/list/for_each.hpp>
 #include <boost/preprocessor/tuple/to_list.hpp>

 #define TUPLE_TO_SEQ_E(r, data, elem) (elem)
 #define TUPLE_TO_SEQ(I, T) \
     BOOST_PP_LIST_FOR_EACH(TUPLE_TO_SEQ_E, _, BOOST_PP_TUPLE_TO_LIST(I,
 T))
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12426#comment:1>
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