The Death of Finalizers

[Simon Marlow]

> | In the meantime, I'm glad we have got a new function
> |    atomicModifyIORef
> | which I for one will use, when it gets into GHC's regular release.
> 
> Just before this gets out of the door... any chance of calling it
> 
> 	modifyIORef
> 
> and documenting that it's atomic?  Sometimes names can get too long!
> 
> Not a big deal though.

It has a different type:

  atomicModifyIORef :: IORef a -> (a -> (a,b)) -> IO b
  modifyIORef :: IORef a -> (a -> a) -> IO ()

we could either
 
1. specify that modifyIORef is also atomic.  That is useful,
   because using an atomic version of modifyIORef would be
   faster than using atomicModifyIORef if you don't need a
   return value.  However, the atomic version of modifyIORef
   would be slower than the non-atomic version.

2. add atomicModifyIORef_, with the same signature as modifyIORef.

I don't really have strong feelings either way, but I think I'd be
slightly inclined towards (2) if anything.

Cheers,
	Simon