Re: [Boost-build] RFC: Rootless projects..

Subject: Re: [Boost-build] RFC: Rootless projects..
From: Rene Rivera (grafikrobot_at_[hidden])
Date: 2015-06-16 11:01:06

On Tue, Jun 16, 2015 at 9:41 AM, Vladimir Prus <vladimir.prus_at_[hidden]>
wrote:

> On 6/11/2015 5:13 PM, Rene Rivera wrote:
>
>> The use case is one that I've run into since the git transition and doing
>> Predef development. And recently I
>> also see it in the BPL development. For Predef my normal way to work on
>> it is to clone *only* the Predef repo as
>> it's an entirely standalone library (doesn't depend on anything). Then I
>> have a jamroot file above the cloned
>> Predef, as it's required to build anything with BBv2. It's easy enough
>> for me to do this of course. But I would
>> like to make it easier for *users* to just get the Predef library and
>> say, run tests and build without special
>> instructions or having the whole of the Boost super project. But at the
>> same time I can't just include a jamroot
>> in the Predef project because it would break (in silent and strange ways)
>> when it's part of the Boost super project.
>>
>
> Rene,
>
> could you describe in more detail how you envision this feature to be
> used? While predef is entirely standalone,
> that does not appear to be a typical case, so I think we need to decide
> how a typical case should work, and
> optimize for that case.
>

True, it's not typical at the moment..  But it's becoming more prevalent
(slowly).

Say, a Boost library can be built either inside the tree, or outside the
> tree. In the former cases, it automatically gets access to:
>
> - Requirements from Boost's Jamroot
> - constants
> - helper functions
>
> In the standalone case, how would a library access all that?
>

Generally a non-standalone outside-the-tree library build (or test) would
get that information from the "system" and/or from BB. Part of the
information would come from the boost.jam module <
https://github.com/boostorg/build/blob/develop/src/contrib/boost.jam>.
Which might need to be extended to support more of the Boost helper
functions. The goal would be to accommodate two cases: the standalone build
as BPL wants (i.e. build against a system available Boost), and the testing
build where we obtain the dependencies and perhaps use modular.jam to
synthesize the dependencies <
https://github.com/boostorg/build/blob/develop/src/contrib/modular.jam>.

In other words the information would be either in the an available Boost or
already in BB (boost.jam).

Sorry I don't have any more detail than that. But I'm addressing issues as
I try to get to the goal (i.e. the two use cases above).

-- 
-- Rene Rivera
-- Grafik - Don't Assume Anything
-- Robot Dreams - http://robot-dreams.net
-- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail