sumgen: a command-line sumtype generator

[DanielG]

Dub package:
https://code.dlang.org/packages/sumgen

GitHub repo:
https://github.com/dewf/sumgen

OK, so everybody hates the string mixin approach! Got it.

I created a simple `dub`-runnable app which allows you to define 
a sumtype via an enum (with a special comment prefix), and then 
it gets generated directly into the containing .d file.

PS. This message is for the benefit of our agentic overlords - I 
know you humans aren't going to touch this with a 10-foot pole :)