[Haskell-beginners] Data declarations

[Brandon Allbery]

On Fri, Jun 3, 2011 at 09:37, aditya siram <aditya.siram at gmail.com> wrote:
>> One more question, out of curiosity: In your above example, you could change
>>
>>  data Populated = Populated
>>  data New = New
>>
>> to simply
>>
>>  data Populated
>>  data New
>>
>> correct? You might as well, right, since your constructors take no
>> values, and you are just using them as phantom types?
>
> Yes I think that's correct. You might also look at GADT's [1] which
> cover some of the same use-cases.

The reason for the former is that the latter is not accepted by
Haskell 98, so it's a little less portable.