Replacing the Prelude

Ashley Yakeley
Mon, 3 Jun 2002 18:06:59 -0700


At 2002-05-14 07:17, Simon Peyton-Jones wrote:

>Ashley writes
>| > I was hoping to do something similar for 'do' notation by redefining
>| > (>>), (>>=) etc., but unfortunately GHC is quite insistent 
>| that 'do' notation quite specifically refers to GHC.Base.Monad 
>Dylan replies
>| I'm surprised that ghc uses the fromInteger and fromRational 
>| that are in scope; I thought there was general agreement that 
>| it should use the Prelude.from{Integer,Rational} in scope.
>Ashley is referring to a GHC extension.  Normally, GHC uses
>Prelude.fromInteger etc, regardless of what is in scope.  But if you
>say -fno-implicit-prelude, GHC will instead use whatver fromInteger
>is in scope.  (This is documented in the manual.)
>Ashley's question, as I understand is whether something similar
>could be done for monads. 
>Answer: I think so, without much bother.   I'm beavering away on
>a Haskell workshop paper at the moment, but ping me in a fortnight
>to do it.
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