Re: Implementing NSFastEnumeration

On Thu, Oct 1, 2009 at 9:13 AM, Christiaan Hofman <[email protected]> wrote:
>
> An important question I have is: which variable should eventually hold the
> objects to return? As the NSFastEnumeration doc says that stackbuf is "A C
> array of objects over which the sender is to iterate", which would suggest
> that that's where the objects should be returned. However I saw this blog at
> <http://cocoawithlove.com/2008/05/implementing-countbyenumeratingwithstat.html>
> that has some samples that suggest that the real place to return the objects
> is in state->itemsPtr.

Yes, the real place to return the objects is state->itemsPtr. The
stackbuf argument points to a C array you can fill with your objects
if you're not already using a C array to hold them. You *can* use that
buffer, but you don't have to, and in some situations you probably
won't want to.

The first example above is for classes that already have a C array
that they simply want to return as-is. It simply assigns the existing
array pointer to state->itemsPtr, and ignores the space provided in
stackbuf.

The second example is for classes that don't have an existing C array.
It fills the array pointed to by stackbuf, then assigns stackbuf to
state->itemsPtr.

sherm--

-- 
Cocoa programming in Perl: http://camelbones.sourceforge.net