Re: [boost] [MPL] A Proposal

Subject: Re: [boost] [MPL] A Proposal
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2016-02-29 03:45:47

On 2016-02-29 06:48, Edward Diener wrote:
> On 2/28/2016 7:13 PM, Andrey Semashev wrote:
>> On Mon, Feb 29, 2016 at 2:17 AM, Bruno Dutra <brunocodutra_at_[hidden]>
>> wrote:
>>> Dear Community,
>>
>> [snip]
>>
>>> My proposal is to make Metal officially into a new revision of
>>> Boost.MPL's
>>> API, essentially MPL2 as the original proposal by Robert Ramey put it,
>>> merging both into one single TMP library. The idea would be to provide a
>>> thin proxy for the current Boost.MPL API which would have two backends
>>> configurable by preprocessor switches: the original implementation and a
>>> another one based on Metal.
>>
>> I don't think it needs to be controlled with preprocessor switches. In
>> fact, it's best to avoid config macros as much as possible because it
>> complicates the use of the library in other libraries.
>
> I disagree with this. Simply because you are compiling with c++11 on up
> will not necessarily mean that you want to use the Metal additions to
> Boost.MPL rather than the current Boost.MPL. Certainly the programmer
> should have a choice even when C++11 is be used in the compilation.

I don't see a use case where you would want a C++03 implementation on a 
C++11 capable compiler. On the other hand I can easily see the situation 
where several libraries using Boost.MPLv2 conflict because they have 
defined different config macros for it.