Right. That's an option. On Tue, Aug 23, 2011 at 10:31 PM, Simon Marlow <marlo...@gmail.com> wrote: > You could make it a precondition of copyArray#, although that's slightly > less pleasant from a user's perspective. > > Cheers, > Simon > > On 23/08/11 21:04, Johan Tibell wrote: >> >> It could well be that it's some later primop that's failing due to the >> empty size, like my new copyArray# primop. If that's the case I could >> fix it but I would probably would have to add a branch to the >> copyArray# primop, which I'm reluctant to do. >> >> On Tue, Aug 23, 2011 at 9:47 PM, Simon Marlow<marlo...@gmail.com> wrote: >>> >>> 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 >>>>>> >>>>>> _______________________________________________ >>>>>> Glasgow-haskell-users mailing list >>>>>> Glasgow-haskell-users@haskell.org >>>>>> http://www.haskell.org/mailman/listinfo/glasgow-haskell-users >>>>> >>>>> >>> >>> > >
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