[Haskell-cafe] Monad instance for Data.Set, again

Ganesh Sittampalam ganesh at earth.li
Fri Mar 28 18:20:55 EDT 2008

On Fri, 28 Mar 2008, Wolfgang Jeltsch wrote:

> But it is possible to give a construction of an Ord dictionary from an 
> AssociatedMonad dictionary.  See the attached code.  It works like a 
> charm. :-)

This is really cool, and with much wider applicability than restricted 
monads; it gives us a general way to abstract over type class constraints.

The NewMonad class is also very straightforward and I think will cause 
much fewer type-checking headaches and large type signatures than Oleg's 


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