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Subject: Re: P2473R0: Distributing C++ Module Libraries
From: Bjarne Stroustrup (bjarne_at_[hidden])
Date: 2021-10-17 10:39:07


On 10/16/2021 12:06 PM, Daniel Ruoso wrote:
> On Sat, Oct 16, 2021, 11:14 Bjarne Stroustrup via SG15
> <sg15_at_[hidden]> wrote:
>
> Maybe, for the benefit of "the rest of us" you might jointly
> compose a *brief* explanation of what problems have to be addressed
>
>
> The first paper we discussed last month covered the requirements. As
> stated on the abstract of this paper, it is meant as a proposal to
> address the requirements laid out in the first.
>
> But, I'll try to summarize the questions we're trying to answer one
> more time:
>
>  1) how does an organization distribute a C++ module library as a
> prebuilt artifact to another organization that may use a different,
> but ABI compatible, compiler?
>
>  2) how does an organization that consumes prebuilt C++ module
> libraries from other organizations discover where the modules are and
> how they are supposed to be parsed in order to produce the BMI for the
> current compiler?
>
>  3) how does an organization perform static analysis on a project
> producing and consuming modules without having to do a tightly coupled
> integration with the build system? (This is something that can be
> achieved today with the compilation database).

Does everyone agree on this formulation of the problem?

>
> and what alternatives there are.
>
> So far, the implementations have focused only on situations where the
> build system has full control over all the source code providing and
> consuming modules.
>
> There currently is no implementations that would work for C++ module
> libraries in, for instance, a Linux distribution.
>
> Eventually, the basic idea of the adopted standard (assuming we
> can agree on one) should be explainable to novices in a single
> short paragraph.
>
> The proposed convention of this paper is: you can map the module name
> to a file name, and you look it up based on a module search path.

and if I understand the discussion correctly, objections are that

 Â Â Â  (1) makes he meaning of a module name dependent on all details of a
file system convention

 Â Â Â  (2) significantly slows down compilation by forcing lookup of many
long file names

Did I get that right? What I am looking for is agreement of a
formulation among "stakeholders" (however defined).

>
> Daniel



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