type class Boolean

[Johannes Waldmann]

[I sent this to -cafe by mistake]

> most useful kind of instance would be symbolic booleans

Yes. Ersatz has this:

https://hackage.haskell.org/package/ersatz-0.4.8/docs/Ersatz-Bit.html#t:Boolean

I also use this class (re-exported) in
https://hackage.haskell.org/package/obdd

Then modules typically start with

import Prelude hiding ( not, and, or, (&&), (||) ) -- possibly more
import Ersatz

slightly annoying but you get used to it ...

- J.