An Array# of size zero is a perfectly reasonable thing. If it doesn't work, it should (and I vaguely recall making it work at some point in the past, but perhaps I failed to add a test and as a result it has rotted...)

Cheers,
        Simon

On 22/08/11 17:08, Johan Tibell wrote:
I agree (unless it has a performance cost). I had to fix a couple of
bugs in my code associated with generating zero-length arrays.

On Mon, Aug 22, 2011 at 5:54 PM, Edward Kmett<ekm...@gmail.com>  wrote:
It would still be nice to have a consistent base case.

On Mon, Aug 22, 2011 at 3:43 AM, Johan Tibell<johan.tib...@gmail.com>
wrote:

On Mon, Aug 22, 2011 at 5:55 AM, Edward Z. Yang<ezy...@mit.edu>  wrote:
stg_newArrayzh in rts/PrimOps.cmm doesn't appear to give any indication,
so this might be a good patch to add.  But I'm curious: what would
allocating Array#s of size 0 do? Null pointers? That sounds dangerous...

I would imagine that a zero sized array would be a StgArrPtrs header
with its size field set to 0. It's not a very useful thing to have, I
admit. If someone (Simon?) can confirm that we don't intend to support
zero-length array I'll push a patch that adds a comment.

Johan

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