[Haskell-cafe] Newbie question (again!) about phantom types

[David F. Place]

On Aug 8, 2007, at 11:16 AM, peterv wrote:

> I’m having difficulty to understand what phantom types are good  
> for. Is this
> just for improving runtime performance?
>
>

I found phantom types to be useful in the implementation of bit-wise  
set operations.  You can find the code Edison:

http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ 
EdisonCore-1.2.1

in the Data.Edison.Coll.EnumSet module.

David F. Place
mailto:d at vidplace.com