[Haskell-cafe] Re: ANN: data-category, restricted categories

[Lennart Augustsson]

Of course Haskell' should have an empty case.  As soon as empty data
declarations are allowed then empty case must be allowed just by using
common sense.

On Tue, Mar 30, 2010 at 11:03 PM, Ashley Yakeley <ashley at semantic.org> wrote:
> wagnerdm at seas.upenn.edu wrote:
>>
>> I believe I was claiming that, in the absence of undefined, Nothing and
>> Nothing2 *aren't* isomorphic (in the CT sense).
>
> Well, this is only due to Haskell's difficulty with empty case expressions.
> If that were fixed, they would be isomorphic even without undefined.
>
> --
> Ashley Yakeley
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