[Haskell-cafe] Data.EnumMap ?

Adam Gundry adam at well-typed.com
Tue Mar 31 19:15:43 UTC 2015

Dear Johannes,

On 31/03/15 19:06, Johannes Waldmann wrote:
> @Andres
>> https://hackage.haskell.org/package/EnumMap
> I was not aware. But that looks like an actual copy of the IntMap code,
> so it does not get maintained/updated? 
> That's why I was thinking of a wrapper module only.

There's also


so this must be a good idea, since it's come up so many times. :-)

I've not looked at the performance overhead of this approach, but I have
used something quite similar, which uses Coercible instead of Enum. Of
course, that works only for newtypes of Int, but it is guaranteed to be


Adam Gundry, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com/

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