[David]
I am thinking, indeed, of a subset of the facilities in the Clang’s modulemap experiment: a mapping from a module name to where to find the corresponding BMI – no filesystrem poking adventure to discover something. It wouldn’t shut down
the door to possible multiple module interface stored in the same file. I am unsure of why that is considered “extra complexity”.
-- Gaby
From: David Blaikie <dblaikie@gmail.com>
Sent: Friday, October 15, 2021 1:41 PM
To: sg15@lists.isocpp.org
Cc: Gabriel Dos Reis <gdr@microsoft.com>; Daniel Ruoso <daniel@ruoso.com>
Subject: Re: [SG15] P2473R0: Distributing C++ Module Libraries
-
[1] which wouldn't preclude the support for module map files, in fact I can see a build system build a module map file for the local modules with a fallback to path-based lookup for external libraries
Why is the module map file approach being discounted or not pursued in favor of the current proposal?
I think there's a misunderstanding here.
The question is: on an arbitrary system with arbitrary libraries being made available to the build system as pre-built artifacts, how is the module map going to be assembled for a given translation that depends on modules provided by those
external libraries?
Might be some talking past each other here, maybe?
Gaby: What "module map file approach" are you referring to - could you provide more details or a link? Do you mean something like (or exactly) Clang's .modulemap files, for instance? ( https://clang.llvm.org/docs/Modules.html#module-maps
)
I think one of the problems with modulemap files is that you can only have one per directory (module.modulemap) for discovery - so that's perhaps what Daniel's responding to: How do you build the modulemap for your system if you were to do this - since you'd
have a bunch of different libraries that all need to share a single module.modulemap file, I think?
If we had one modulemap per public interface unit thingy - then that's roughly what Daniel's proposing, I think. A way to map them to the filesystem/find associated instructions next to the module interface file.