[Haskell-beginners] why is there no typeclass common to all containers?

[Alex Rozenshteyn]

Map is (you map over the values, not the keys).

On Wed, Jun 1, 2016 at 1:14 AM Tony Morris <tonymorris at gmail.com> wrote:

> Map and Set are not.
> On 01/06/2016 8:57 AM, "Jeffrey Brown" <jeffbrown.the at gmail.com> wrote:
>
>> In Haskell typeclasses are based on what you want to do with something.
>> If, for instance, you want to be able to map over a container, you can make
>> it an instance of class Functor -- which all the standard containers (List,
>> Map, Set, Tree, Maybe ...) already are.
>>
>> On Tue, May 31, 2016 at 3:26 PM, Silent Leaf <silent.leaf0 at gmail.com>
>> wrote:
>>
>>> In fact it all comes down to trying to add partially a feature absent
>>> from the Haskell language, which is the ability to distinguish values both
>>> on name *and* on type --thus allowing two variables of the same name if
>>> they have different types.
>>> Honestly i don't see the drawback of that name system, but i guess there
>>> must be one otherwise it'd have been chosen by default instead of the
>>> typeblind current name system.
>>>
>>>
>>> Le mercredi 1 juin 2016, Silent Leaf <silent.leaf0 at gmail.com> a écrit :
>>> > All in the title. I haven't used them much, but I saw Map or Vector
>>> types were forcing the user to use qualified functions unless you want
>>> nameclash with the more basic, typically list-oriented functions.
>>> > So, why not have a massive, general purpose interface so the type only
>>> can separate between containers --which would allow for cross-container
>>> polymorphism, i suppose, more easily, even though it's not necessarily the
>>> most widespread need.
>>> > So, do i miss something? Is there in fact a class of that kind? If so
>>> why not?
>>> > Thanks in advance! :)
>>>
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>>>
>>
>>
>> --
>> Jeffrey Benjamin Brown
>>
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