RE: running LUA code step by step

["Curt Carpenter" <curtc@...>]

Can you explain how that works? Does the yield call inside a registered
C function not return until some other state yields back to the first
state? 
If so, I don't understand how that's possible (without blowing the stack
out, for example). 
If not, it's not exactly the same thing.

Thanks,

Curt

-----Original Message-----
From: Roberto Ierusalimschy [mailto:roberto@inf.puc-rio.br] 
Sent: Saturday, March 16, 2002 4:14 AM
To: Multiple recipients of list
Subject: Re: running LUA code step by step 


> 1) Fire up new fibers (and call lua_newthread) for new objects which 
> need their own script execution/stack/lua_state
> 2) Keep a list of objects that are ready to execute. Loop over all 
> objects and switch to their fiber.
> 3) In each object, figure out when they want to yield, either by a 
> line/call hook, or by a call into a registered C function that 
> indicates they need to wait (like a call that blocks on something out 
> of its control).
> 4) When an object is ready to yield, switch back to the primary fiber.
> 5) Depending on your needs, have some plan to add objects back to the 
> ready list. If you want all objects to execute code on every cycle, 
> then maybe you don't need a ready list, but I use it to mark scripts 
> that are ready to continue after having some condition met that they 
> are blocked on.

You should be able to do exactly the same thing with coroutines in
Luaw4. (The only drawback is that currently you cannot yield inside a
linehook; we will correct that. But you can yield inside a registered C
function that indicates they need to wait.)

-- Roberto