New library: argparse, for parsing CLI arguments

[Steven Schveighoffer]

On 10/13/21 9:13 PM, Andrey Zherikov wrote:
> On Thursday, 14 October 2021 at 00:35:11 UTC, Bill Baxter wrote:
>>
>> Not sure how much change there is over "classic" gflags, but 
>> https://abseil.io/docs/cpp/guides/flags is what google now uses 
>> internally.
>>
> 
> Abseil version suggests not to put flags into multiple .cpp files:
> - `Allows distributed declaration and definition of flags, though this 
> usage has drawbacks and should generally be avoided`
> - `Prefer to define flags only in the file containing the binary’s 
> main() function`
> - `Prefer to reference flags only from within the file containing the 
> binary’s main() function`
> 
> So I'm a bit confused about supporting this use case

Yeah, there is a problem with doing this the D way, and that's with 
module constructors. You can run into cycles.

When I implemented database migrations in my application, I set it up so 
I could run module ctors that set up each migration near the location 
where I'm defining the data structures, but I ended up having to put 
them all into a dedicated `migrations` module to avoid the cycles.

D could definitely use a way to specify a no-dependency module ctor/dtor.

-Steve