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

[Peter Hall]

> As for why Haskell doesn't allow natural overloading of any function name
merely by choosing another name, does anyone know?

Haskell requires that overloaded functions are part of a typeclass. This
isn't a big requirement - you can easily make any type into an instance of
a new typeclass.

The reason why this is important is that it ensures that the meaning and
intent of the function are the same, not just a coincidental naming
collision.


Peter


On 1 June 2016 at 18:18, Silent Leaf <silent.leaf0 at gmail.com> wrote:

> map and set are not what? I didn't get it.
>
> That's cool, I'll look into it!
> As for why Haskell doesn't allow natural overloading of any function name
> merely by choosing another name, does anyone know?
>
>
> Le mercredi 1 juin 2016, Alex Rozenshteyn <rpglover64 at gmail.com> a écrit :
> > 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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> >>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
> >>>>
> >>>
> >>>
> >>>
> >>> --
> >>> Jeffrey Benjamin Brown
> >>> _______________________________________________
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> >>>
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>
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