[Haskell-cafe] Is it possible to represent such polymorphism?

[Du Xi]

Quoting Victor Gorokgov <me at rkit.pp.ru>:

> 02.10.2011 19:55, David Barbour пишет:
>> Use TypeFamilies.
>>
>>
>> {-# LANGUAGE TypeFamilies #}
>> ...
>> type family FType a :: *
>> type instance FType Char = Float
>> type instance FType Double = Int
>>
>> class ExampleClass a where
>> f :: a -> FType a
>>
>
> Better to include type in class.
>
> class ExampleClass a where
> type FType a
> f :: a -> FType a
>
> instance ExampleClass Char where
> type FType Char = Float
> f char = ...
>
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I guess this is what I want, thank you all. Although I still wonder  
why something so simple in C++ is actually more verbose and requires  
less known features in Haskell...What was the design intent to  
disallow simple overloading?