Add meaningful instances to ZipList
wren ng thornton
wren at freegeek.org
Mon Dec 19 22:46:33 CET 2011
On 12/17/11 1:37 PM, Daniel Peebles wrote:
> I noticed that the ZipList newtype in Control.Applicative has no derived
> instances at all. We can't show a ZipList, check it for equality, or do
> anything to it except unpack it or treat it like an Applicative or Functor.
> It seems fairly uncontroversial to suggest adding some instances for it,
> but there are some minor questions to address: the obvious instances to add
> might be Eq, Ord, Show, Read, and possibly Typeable and/or Data.
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