[draegtun]

Io also gets coroutines right and makes them very easy to use:

* http://www.iolanguage.com/scm/io/docs/IoGuide.html#Concurren...

* http://www.iolanguage.com/scm/io/docs/reference/Core/Core/Co...

Probably no surprise though because Lua was one of the influences behind Io design/implementation (full list of influencers from http://www.iolanguage.com/):

    * Smalltalk (all values are objects, all messages are dynamic),
    * Self (prototype-based),
    * NewtonScript (differential inheritance),
    * Act1 (actors and futures for concurrency),
    * LISP (code is a runtime inspectable/modifiable tree)
    * and Lua (small, embeddable).