Re: Empty Datatypes in GHC 5?

Ashley Yakeley writes:

data Zero; data Succ n;

Unfortunately this is contrary to the Haskell Report. Nevertheless, Hugs allows it. But GHC, apparently, does not.

Note that Hugs allows it principally so that we can write the following in the Prelude: data Float data Double data Int data Char ... That it's useful for other things is pretty much incidental. -- Alastair Reid reid@cs.utah.edu http://www.cs.utah.edu/~reid/