[Haskell-beginners] Heterogeneous Lists

[Mateusz Kowalczyk]

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On 28/05/13 14:41, harry wrote:
> Magnus Therning <magnus <at> therning.org> writes:
> 
>> Just to make sure... I guess you've already read 
>> http://www.haskell.org/haskellwiki/Heterogenous_collections
>> right?
> 
> Yes, I'm asking why Haskell doesn't allow this directly. I'm
> already using a workaround.
> 
> 
> _______________________________________________ Beginners mailing
> list Beginners at haskell.org 
> http://www.haskell.org/mailman/listinfo/beginners
> 
Simply because Haskell's lists are a homogeneous data structure by nature.

Consider:
data List a = Nil | Cons a List

It doesn't do heterogeneous lists by default because it was never
meant to. I don't see where the disappointment comes from. It's the
same in majority of typed languages. I don't see why you would expect
to be able to make have a heterogeneous list because you can do it
with interfaces in some other language. To begin with, typeclasses are
not interfaces.

Just so you know, you're probably doing it wrong if you're using `a
workaround' to have a heterogeneous list.
- -- 
Mateusz K.
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