Re: [Vala] The state of closures

["Sam Liddicott" <sam liddicott com>]

On 28/04/11 16:08, Luca Bruno wrote:
> On Thu, Apr 28, 2011 at 03:58:32PM +0100, Sam Liddicott wrote:
> > This feature may be less useful for vala if it does stack-tear-down
> > for interruptable functions, but perhaps more suited if it uses
> > co-routines with different stacks so that the stack is switched and
> > not torn-down when an interruptable function is interrupted.
> Yes that's the problem, with vala you may pass the closure to another
> function and exit from the current scope, while with gcc nested function
> the stack is lost once you exit the outer function.

And it's hard to control this or know when it is happening by accident.

I wonder if it is worth considering libpcl or other co-routine libraries 
- it would take away the need for a lot of effort to get fuller closure 
support.

I've also been thinking of ways to detect when vala closures go stale - 
one way is for the data pointer to be indirected via a heap allocated 
pointer. This could be set to null by the outer function when it exits, 
and so any use after this point can be detected - as when the wrapper 
trampoline function is executed it will detect that the data pointer 
points to NULL instead of pointing to the actual data pointer.

Sam