DIP1044---"Enum Type Inference"---Formal Assessment

[Paul Backus]

On Thursday, 11 May 2023 at 00:56:03 UTC, ryuukk_ wrote:
> Don't you find this code easier to read and review?
>
> ```D
>         if (target.os == .Windows)
>         {
>             item("windows");
>         }
>         else
>         {
>             item("posix");
>             if (target.os == .linux)
>                 item("linux");
>             else if (target.os == .OSX)
>                 item("osx");
>             else if (target.os == .FreeBSD)
>             {
>                 item("freebsd");
>                 item("bsd");
>             }
>             else if (target.os == .OpenBSD)
>             {
>                 item("openbsd");
>                 item("bsd");
>             }
>             else if (target.os == .Solaris)
>             {
>                 item("solaris");
>                 item("bsd");
>             }
>         }
>         arrayEnd();
> ```

Honestly, not really. I've never looked at this part of DMD, and 
without context, I'd have no idea where the symbols `Windows`, 
`linux`, `FreeBSD`, and so on were coming from. Having it 
explicitly spelled out at the usage site--either via qualified 
names (`Target.OS.Windows`) or a local alias (`alias TOS = 
Target.OS`) makes it trivial to understand what's being referred 
to.

In fact, for this particular example, there are actually two 
enums in the DMD source code that these symbols could be coming 
from: `enum TargetOS` in `cli.d`, and `enum OS` in `target.d`. So 
you would have to scroll up and look at the imports to 
disambiguate.