Re: [boost] [modularization] proposal and poll

Subject: Re: [boost] [modularization] proposal and poll
From: Peter Dimov (lists_at_[hidden])
Date: 2014-05-30 13:15:53

Glen Fernandes wrote:
> On Fri, May 30, 2014 at 9:02 AM, Peter Dimov <lists_at_[hidden]> wrote:
> > exception:
> >    adds smart_ptr
> >    adds tuple
>
> This was the most surprising to me. I assumed, and now really desire, 
> exception to not have any other dependencies.

It's a false dependency. 'exception' only depends on 'tuple' if you include 
one specific header. (I think that Emil was considering its removal.)

In addition, we only use throw_exception.hpp, which actually doesn't even 
need 'exception'; it's (almost) self-contained. It could be extracted into 
its own 'throw_exception' module.

Neil Groves wrote:

> I'm not sure this report is giving an accurate representation of the true 
> dependencies of smart_ptr.

It contains a lot of false dependencies that are brought in because module X 
needs Y1.hpp in module Y, which also contains Y2.hpp, which needs Z, which 
is not needed by X.

But that is just how module-level dependencies work. If we adopt the simple 
scheme of specifying dependencies on a module basis, X will list Y and Y 
will list Z, and we'll get the result I posted.

I could have built the transitive closure of the actual #includes, and it 
would have given a different result, but that's not what I'm emulating.