[Haskell-cafe] Re: Adding Ord constraint to instance Monad Set?

John Hughes rjmh at cs.chalmers.se
Thu Apr 1 13:21:08 EST 2004

| "Constraints on datatype declarations are a misfeature of Haskell, and
| have no useful effect."
| Is this the final conclusion?

Yes, it is, I believe.  Constraints on data type declarations are a
mis-feature.  I tried to get them removed, but there was some argument
that they could be made useful (see John Hughes's paper "Restricted data
types in Haskell", Haskell workshop 1999), and they stayed. 



Made useful in a way that would solve the problem in this thread, I 
might add. The paper is at


for the curious.


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