Ask HN: Generic Replacement for Rbenv, NVM, GVM?

I have quite a few version managers installed. Each with their own quirks. I really like rbenv but I wish I had a tool that provided that sort of functionality in a generic way that I could use for all the various languages whose versions I have to juggle on a daily basis.

Does such a tool exist?

I found https://github.com/direnv/direnv but I would prefer something that's written in Bash.