[Haskell] Haskell 98 syntax question

Stefan O'Rear stefanor at cox.net
Wed Jan 10 10:10:10 EST 2007


On Wed, Jan 10, 2007 at 03:33:44PM +0100, "Sascha B?hme" wrote:
> Hello,
> 
> referring to the Haskell 98 report as available in the Internet, I have a short question. Section 4.1.3 (Syntax of Class Assertions and Contexts) contains the rule:
> 
> class -> qtycls tyvar
>       |  qtycls ( tyvar atype1 ... atypen ) (n>=1)
> 
> Is there a (simple) practical example of a Haskell type expression using the second line of the above rule?

Prelude> :t \a b -> (Control.Monad.Trans.lift a >> b)
\a b -> (Control.Monad.Trans.lift a >> b) :: (Monad (t m), Control.Monad.Trans.MonadTrans t, Monad m) =>
m a -> t m b -> t m b


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