ANNOUNCE: countable-1.0

Henning Thielemann lemming at henning-thielemann.de
Mon Sep 6 07:01:30 EDT 2010


On Mon, 6 Sep 2010, Ashley Yakeley wrote:

> countable: Countable, Searchable, Finite, Empty classes.
>
>  class Countable, for countable types
>  class AtLeastOneCountable, for countable types that have at least one value
>  class InfiniteCountable, for infinite countable types
>  class Searchable, for types that can be searched over
>  class Finite, for finite types
>  class Empty, for empty types
>  data Nothing, an empty type
>
> Also includes these orphan instances:
>
>  instance (Searchable a,Eq b) => Eq (a -> b)
>  instance (Finite a) => Foldable ((->) a)
>  instance (Finite a) => Traversable ((->) a)
>  instance (Show a,Finite a,Show b) => Show (a -> b)

Why must the domain be finite? I think infinite Strings produced by Show 
are not a problem, since the result of 'show infiniteList' is also 
infinite.


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