Re: RFC: Adding a Hashable type class and HashMap/HashSet data types to HP

On Fri, Nov 19, 2010 at 10:48 AM, Gregory Collins wrote:

On Thu, Nov 18, 2010 at 11:05 PM, Johan Tibell wrote:

...

* A type class for things that can be hashed, Hashable.

class Hashable a where    hash :: a -> Word

BTW,

An issue that needs to be resolved is: "Where should this change go?" We have a couple of options:

 a) Bring http://hackage.haskell.org/package/hashable into the platform

 b) Put the module into base -- probably a -1 for political/logistical reasons

 c) Put it into containers -- probably a -1 because it would force a     containers dependency where there was no containers dependency before.

Right. Putting it into containers would force text/bytestring to depend on containers or vice versa, in order to provide instances. Base or a separate package are the only options I think. Johan