25 Oct
2013
25 Oct
'13
5:05 a.m.
KwangYul Seo
writes: It seems there are three different ways to declare an empty type in Haskell.
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