Re: [boost] [MPL] A Proposal

Subject: Re: [boost] [MPL] A Proposal
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2016-02-28 19:13:01

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.

One of the reasons for using Boost.MPL is to keep the code compatible
with C++03. I assume, with your proposed solution this compatibility
will be preserved, won't it? If so, you could branch the
implementation based on the language version (or rather, the set of
enabled/supported C++11 features).

If you don't plan to keep the code compatible with C++03 then I'd
rather see Boost.Metal as a completely separate library and Boost.MPL
untouched.