Boost logo

Boost :

Subject: Re: [boost] [Spirit-general] [karma][fusion] Signed integer members of Boost.Fusion adapted ADTs are not output correctly with Boost.Spirit.Karma rules
From: Torsten Maehne (Torsten.Maehne_at_[hidden])
Date: 2011-12-29 08:43:46

Hello Jeroen,

On Thu, 29 Dec 2011 00:36:28 +0100, Jeroen Habraken wrote:

> Hi,
> On 28 December 2011 15:38, Torsten Maehne <Torsten.Maehne_at_[hidden]> wrote:
>> Hello Jeroen,
>> Jeroen Habraken <vexocide_at_[hidden]> writes:
>>> Hi,
>>> On 27 December 2011 19:24, Torsten Maehne <Torsten.Maehne_at_[hidden]>
>>> wrote:
>>>> Hello Jeroen,
>>>> thank you for looking on my test case on Boost trunk! Unfortunately,
>>>> Boost trunk doesn't seem to be in a good shape currently for my test
>>>> case, as it seems to trigger additional unrelated problems. Boost
>>>> 1.48.0 seems to be currently a more suitable starting point for a
>>>> diagnosis of the original problem.
>>>> Please see my comment below regarding your suggestion.
>>>> Jeroen Habraken wrote:
>>>>> Hi,
>>>>> On 27 December 2011 00:51, Torsten Maehne <Torsten.Maehne_at_[hidden]>
>>>>> wrote:
>>>>>> Hello,
>>>>>> I'm using Boost.Spirit.Karma to format the output of some nested
>>>>>> structs (direct access of the public member variables) and abstract
>>>>>> data types (ADTs) (access to the private member variables via
>>>>>> getters and setters)
>>>>>> in my code. I'm using Boost.Fusion to adapt the ADTs into a
>>>>>> sequence of values of primitive data types for output with
>>>>>> Boost.Karma. This worked fine till Boost 1.44. Since Boost 1.45 up
>>>>>> till 1.48 and the current Boost trunk (I tested svn revs 75505,
>>>>>> 75963, and 76196) the output of unsigned integer members of
>>>>>> Boost.Fusion-adapted ADTs doesn't work anymore --
>>>>>> even though I took into account the change in the name of macro
>>>>>> the additionally required header
>>>>>> boost/spirit/include/support_adapt_adt_attributes.hpp.
>>>>>> The problem is demonstrated in the attached test case for rational
>>>>>> number ADTs and structs, which use signed integer member variables.
>>>>>> Compilation of this test case against Boost 1.44.0 will succeed and
>>>>>> it will run without any errors. Compilation of this test case
>>>>>> against Boost 1.45.0 and 1.46.1 will fail. Compilation against
>>>>>> Boost 1.47.0 and 1.48.0 will succeed, but the output of negative
>>>>>> values of signed integer members of Boost.Fusion-adapted ADTs will
>>>>>> be wrong. The minus sign is output correctly, but it is followed by
>>>>>> a wrong value, which seems to be yielded by a cast from a signed to
>>>>>> an unsigned integer value instead of taking the absolute value of
>>>>>> the signed integer value. This has been observed on Mac OS X 10.7.2
>>>>>> (x86_64) with Xcode 4.2 using Apple's g++ 4.2.1, Apple's clang++
>>>>>> 3.0. Interestingly, compiling the test case against Boost 1.47.0 or
>>>>>> Boost 1.48.0 using MacPorts g++
>>>>>> 4.5.3, will yield more output checks to fail for
>>>>>> Boost.Fusion-adapted ADTs used in Karma output rules.
>>>>>> Compilation against Boost from the Subversion trunk (I tested revs.
>>>>>> 75505, 75963, and 76196) does only succeed using Apple's clang++
>>>>>> 3.0 and execution will yield the same wrong output for negative
>>>>>> values of signed integer members of Boost.Fusion-adapted ADTs.
>>>>>> Compilation fails with Apple's g++ 4.2.1 and MacPorts g++ 4.5.3.
>>>>>> I'm not able to locate the root cause for this problem, whether it
>>>>>> is in Boost.Fusion or Boost.Spirit.Karma. I would appreciate any
>>>>>> help to resolve this annoying issue. Until a solution is found, I'm
>>>>>> stuck with Boost 1.44.0.
>>>>> Several things seem to play a role, but I've had a look at as to why
>>>>> the code doesn't compile using boost-trunk and found the cause to be
>>>>> an ambiguity:
>>>>> boost/typeof/native.hpp:30:9: error: reference to 'enable_if' is
>>>>> ambiguous boost/utility/enable_if.hpp:36:10: error: candidates are:
>>>>> template<class Cond, class T> struct boost::enable_if
>>>>> boost/test/tree/decorator.hpp:184:23: error:                 class
>>>>> boost::unit_test::decorator::enable_if
>>>>> As enable_if is often used without being fully qualified this breaks
>>>>> in a major fashion. Since boost/test/tree/decorator.hpp seems to be
>>>>> quite new (added 2011-10-02 11:00:16 +0200) it might be best fixed
>>>>> there.
>>>> On my side, I was not able to reproduce the "enable_if is ambiguous"
>>>> error related to Boost.unit_test that you've observed. I tried with
>>>> Apple g++ 4.2.1 and MacPorts g++ 4.5.3.
>>> Actually, you are. The logs
>>> and
>>> show:
>>> /opt/boost-trunk/include/boost/fusion/iterator/equal_to.hpp:77: error:
>>> expected nested-name-specifier before ‘enable_if’
>>> /opt/boost-trunk/include/boost/fusion/iterator/equal_to.hpp:77: error:
>>> expected initializer before ‘<’ token
>>> These occur because the code states "typename enable_if<Cond,
>>> T>::type" and the typename doesn't make sense in combination with
>>> boost::unit_test::decorator::enable_if. When you remove the typename
>>> (which is essentially what I did when debugging) you'll get the
>>> ambiguity error.
>> Thanks for these explanations. Indeed this issue is distinct from my
>> original problem and maybe should be assigned an own Trac ticket.
> Yes, please do.

For your information, I just created Boost trac ticket #6331 to report
the conflict between template<class Cond, class T> struct
boost::enable_if and class boost::unit_test::decorator::enable_if. I hope
that it gets soon picked up by the Boost.Test authors.

>>>>>> Please note that I also submitted a bug report on this issue more
>>>>>> than 6 weeks ago without any reaction so far:
>>>>>> <>
>>>> This ticket contains compile logs of my tests with the two mentioned
>>>> compilers.
>>>>>> Best regards,
>>>>>> Torsten Maehne
>>>>> Note: I've included boost_at_[hidden] in the discussion.
>>>> I hope that someone has an idea how to proceed further to separate
>>>> the different problems. My original test case was designed to just
>>>> expose the signed integer output problem. I used Boost.unit_test to
>>>> facilitate its integration into a test suite. Now it seems to cause
>>>> further side effects... at least on your side.
>>>>> Kind regards,
>>>>> Jeroen Habraken

Best regards,


Boost list run by bdawes at, gregod at, cpdaniel at, john at