"case" of an empty type should have no branches
Roman Beslik
beroal at ukr.net
Sun Oct 9 18:00:43 CEST 2011
On 09.10.11 15:45, Felipe Almeida Lessa wrote:
> On Sun, Oct 9, 2011 at 8:26 AM, Roman Beslik<beroal at ukr.net> wrote:
>> Why the following code does not work?
>>> data Empty
>>> quodlibet :: Empty -> a
>>> quodlibet x = case x of
>> "parse error (possibly incorrect indentation)"
> Works for me:
>
> data Empty
>
> quodlibet :: Empty -> a
> quodlibet x = case x of _ -> undefined
This is a solution. Thanks.
> I'd prefer to define something like
>
> data Finite = Zero | Plus Finite
>
You just defined the set of natural numbers which is infinite. ;)
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