rdmd configuration files

[Lodovico Giaretta via Digitalmars-d]

On Thursday, 11 August 2016 at 21:33:24 UTC, Jonathan Marler 
wrote:
> On Thursday, 11 August 2016 at 20:44:12 UTC, Lodovico Giaretta 
> wrote:
>> On Thursday, 11 August 2016 at 18:47:05 UTC, Jonathan Marler 
>> wrote:
>>> [...]
>> [...]
>
> I don't necessarily agree or disagree with you, thanks for 
> providing your opinion.  A wrapper script would certainly solve 
> the simple cases.  The con is that it adds an extra layer to 
> the script and every application will have their own solution 
> which makes a project more isolated.  The wrapper script was 
> the first solution that came to my mind but as I thought about 
> configuration files, they seemed worth considering.

I agree that a custom wrapper script has the drawbacks you said.
But I fear that a configuration-file-based system would either 
only solve simple cases or would become very complex and 
difficult to master in order to accomodate to most special uses, 
thus becoming less appealing than a simple script.
A config file format is one more thing to know and to look up: 
"how do I do this with rdmd-config?", while the Internet is full 
of tutorials on "how to do this with bash". The same happens to 
DUB: it allows to do many things when building the project, so 
people asks "how can I do this with DUB?" while it would probably 
be easier to just write a shell script that calls DUB and then 
(or before) does the other thing.
We should avoid reinventing the wheel.

> I'm curious what you think about the more complex operations 
> that configuration files could facilitate. The example I gave 
> was that this could enable a script to use dub package 
> dependencies that are automatically downloaded and built by 
> rdmd, but I'm sure there are other interesting use cases.  An 
> argument could be made that this should go in an external tool 
> rather then rdmd though, but that thought seemed a bit odd 
> since rdmd is already a wrapper around dmd itself, but maybe 
> that's ok.  Do you have any new features rdmd could support if 
> it had configuration files?

I think that many reasonable but not-trivial things can already 
be done with DUB, which allows custom compiler and linker flags, 
custom commands before and after the build, different 
configurations and so on. It is already a very complex 
configuration system, and can also do the job of rdmd ("dub run" 
executes the project, using a cached compiled file if available 
and up to date, as rdmd).
DUB also allows to have single-source packages, where the DUB 
configuration and dependencies are embedded in a comment at the 
beginning of the source, which would be a great solution for your 
example, as it doesn't even require a configuration file.