Re: state of the Lua nation on resource cleanup

[Roberto Ierusalimschy <roberto@...>]

> Roberto wrote:
> > [...]
> >
> > That is, all resources should have an explicit "close" method plus
> > a finalizer that releases it. (Like files from the io library.)  In
> > regular use, the control flow should call the close method for prompt
> > release. On exceptions, a full collection would call the finalizers.
> 
> Hi Roberto.  I'm concerned about some negative consequences this
> solution would have:
> 
>     * negation of incremental GC benefits - the point of the
> incremental garbage collector is to minimize wost-case collection
> cycle duration.  Apps relying on this would be back to square one
> should an exception occur at any time (e.g. a video game might miss
> its frame deadline). [...]

For me, an exception is exactly the kind of thing that justifies the
miss of a frame deadline. (I could even use this as a definition of
what is an exception :)  But this is a matter of taste...


>     * difficulty for Lua implementations - there are a number of Lua
> VM implementations (e.g. Kahlua) which rely on the native GC of some
> particular language rather than porting Lua's memory management.
> [...]

I do not agree with this point. We are not going to restrict Lua design
space because of JVM limitations.


> Besides these, I think this solution overlooks the usefulness of
> having a cleanup mechanism that covers all exit cases.

This is a good point.

-- Roberto