[Haskell-beginners] Type unions

[aditya siram]

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 <aditya.siram at gmail.com> 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 <russ.abbott at gmail.com> 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
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>>
>