[MLton] thread model

[Stephen Weeks]

> > In the NJ 
> > implementation of CML this would probably be done by capturing the 
> > continuation at the scheduling point (the scheduler already uses callcc 
> > so no extra work here), save it, then to restore the thread to the 
> > continuation I have saved by placing the saved continuation on the 
> > scheduling queue inplace of the current continuation for that thread.   
> > The sceduler takes care of the rest  (ignoring for now  the heap etc).   
> > With MLton's one shot continuations, is there a  way to emulate this?
> 
> Maybe, though you will need to dive deep into the threads implementation.  

How about just using MLton.Cont?  To "restore" a thread t1 to
continuation k, simply kill t1 and create a new thread t2 whose sole
behavior is to throw to k.