Simplify some C-style code

[monkyyy]

On Wednesday, 25 December 2024 at 17:20:01 UTC, user1234 wrote:
> What you can do however is to use 
> https://dlang.org/phobos/std_sumtype.html. instead of a the 
> manually defined tagged union.

If he's struggling to define a enum with a mixin I assume he's 
very new and to get this code to work with sumtype would require 
a template map, which would make you a highly competent template 
wizard