Re: Garbage collection (was: Calling C++ class methods from Lua (newbie))

[Rici Lake <lua@...>]

On 17-Oct-05, at 7:59 PM, David Given wrote:

> Yes, it does sound a bit of a nightmare --- I wasn't aware that libgc 
> didn't
> support soft references, for example. Even so, it might be instructive 
> to try
> benchmarking Lua running its own garbage collector on top of libgc; 
> it'd be
> interesting to know in what way it behaved differently. It's also 
> something
> that might be done in the real world, if you happened to write an 
> application
> that embedded Lua and also used libgc.

It's not exactly that libgc doesn't support "soft references". You can 
implement a weak pointer with libgc, which is why I was careful to 
point out that a weak table is not just a collection of weak 
references. A weak table is somewhat more like a collection of 
ephemerons, but afaik there is no simple way to implement ephemerons 
with libgc. If there is, it would be somewhat more attractive, although 
the other stuff I mentioned would still be a problem.

Personally, I don't really think that libgc is the way to go here, 
though, although as you say it might be handy in an environment which 
happened to be using libgc anyway. There are various ways to at least 
get libgc to not get in the way of Lua's garbage collecting, like 
having Lua tell it that it is managing its own memory, thank you very 
much.