Re: Very interesting analysis of "the state of Emacs"

[Richard M Stallman]

    If we are looking at concurrency, there is another paradigm based on
    maintaining multiple internal function call stacks which a scheduler
    can schedule in some fair fashion. I am talking of stackless Python
    implementation. You really do not have multiple threads but get
    simulated concurrency through stack switching.

The idea is to get effective parallel execution for Lisp programs and
redisplay.  This doesn't mean using multiple threads at the C level.
It means using whatever method is convenient.