[ken]

Concurrency is one of those core features which is hard to add after-the-fact, and so the initial design strongly determines the course of the language's life. It requires re-opening such fundamentals as what does it mean to call a function, or assign to a variable.

"Nobody is using Ruby for multithreading" is both cause and effect.

That's why I'm not terribly optimistic about projects like this (or the proposed Swift 6). That's not how these things work. Can you imagine a language which features good concurrency support today (like Erlang or Clojure) having been launched without it, and then announcing 5 (or 25) years later "We're going to address concurrency now"?

[ioquatix]

Completely agree with you and to me that's why it's an exciting challenge. I'm not expecting to solve every problem, but I'm trying to carve out a solution which I think works for these legacy issues. Even if we didn't have a solution for the last 25 years, no harm in adding one now! :)