[Boris]
> It needs to be. Specifically, additional inputs and outputs should
> be reportable ahead of compilation and preferably this should be
> relatively cheap. It needs to be ahead of compilation because inputs
> themselves could be auto-generated. And I am not aware of any build
> system that doesn't require dynamic outputs to be known before invoking
> the tool (build2 certainly doesn't support this and likely never will).

Thanks. I think we are agreeing there. I believe this is the sort of feedback/consideration that needs to go into the design of compile-time code generation feature. I am not saying that the current design violates or does not violate these practical considerations. Just that "implementability" of the core features themselves in a compiler is a necessary condition, but not sufficient to move ahead with it without further constraints.

-- Gaby

-----Original Message-----
From: Boris Kolpackov <boris_at_[hidden]>
Sent: Wednesday, October 30, 2024 6:31 AM
To: Gabriel Dos Reis <gdr_at_[hidden]>
Cc: ISO C++ Tooling Study Group <sg15_at_[hidden]>
Subject: Re: [isocpp-sg15] [P2758] Emitting messages at compile time

Gabriel Dos Reis <gdr_at_[hidden]> writes:

> For modules, the compiler is able to report dependencies. Do we
> have analogous situation here?

It needs to be. Specifically, additional inputs and outputs should
be reportable ahead of compilation and preferably this should be
relatively cheap. It needs to be ahead of compilation because inputs
themselves could be auto-generated. And I am not aware of any build
system that doesn't require dynamic outputs to be known before invoking
the tool (build2 certainly doesn't support this and likely never will).