Re: Coroutines in Lua

[Edgar Toernig <froese@...>]

Stefano Lanzavecchia wrote:
> 
> What I have in mind is Python's microthreads. They are based on a small
> addition to the core (a timeslice parameter) which returns control to the
> registered coroutine handling the task switching (the coroutine is written
> in Python, Lua in our case) once the timeslice is expired (more or less).
> This is almost real pre-emptive...

... while within Lua.  Sounds reasonable.

> ========================
> co1 = coronew("some_function")
> 
> newvariable = 42 -- a very important constant!
> 
> cororesume(co1) -- this causes GC to activate and eventually resume main
> 
> print (newvariable) -- this will print NIL since when the stack for
> -- coroutine 1 was created, newvariable did not exist, therefore when GC
> -- started in coroutine 1 newvariable wasn't linked from any useful place.
> =========================

Hmm...  Are you sure there's no other problem?  This should work!  The
global table is shared between all threads and shouldn't be affected.
And if you really have different L->gt the one of main should have been
freed.  But then even finding 'print' would be pretty difficult ;)

Btw, when working on such things a debug malloc that fills freed memory
may be handy to detect references to stale data.

Ciao, ET.