Re: [Haskell-beginners] Type unions

Sorry I had a typo. Here's working code: data A = A Int data B = B Int f :: Int -> Either A B f x | even x = Left $ A x | otherwise = Right $ B x -deech On Tue, Dec 14, 2010 at 2:29 PM, aditya siram wrote:

Does this help?

data A = A Int

f :: Int -> Either A B f x  | even x = Left $ A x     |  | otherwise = Right $ B x |

-deech

On Tue, Dec 14, 2010 at 2:09 PM, Russ Abbott wrote:

...

Is there a way to get this to work?

data A = Aconstructor Int data B = Bconstructor Int data AorB = A | B f :: Int -> AorB f x   | even x     = Aconstructor x   | otherwise = Bconstructor x

 I get this diagnostic.

Couldn't match expected type `AorB' against inferred type `A'

Since AorB is A or B, why is this not permitted? If instead I write

data AorB = Aconstructor Int | Bconstructor Int

everything works out ok. But what if I want separate types for A and B? Thanks, -- Russ _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners