[Haskell-beginners] Empty type

[AntC]

> KwangYul Seo <skyul <at> company100.com> writes:
>
> It seems there are three different ways to declare an empty type in Haskell.
>
> http://www.haskell.org/haskellwiki/Empty_type
>

Hi KwangYul, it seems someone was playing games writing that page. I suggest 
you look at:

http://www.haskell.org/ghc/docs/7.6.3/html/users_guide/data-type-
extensions.html#nullary-types

So the answer is that there is one way to declare an empty type; and it's 
method 3) from your OP.

I agree with Ben that method 1) is not truly empty.

And I like both Ben's and Kim-Ee's explanations why 2) is kinda empty and 
kinda not. (Trying to use Void will almost certainly make your program loop. 
Using method 1) or 3) won't.)

AntC