[Haskell-beginners] Abstracting Data.List

[Giacomo Tesio]

Thanks, that's a good starting point. What would be the proper name for
such an abstraction in Haskell?

In C# it would be Enumerable (and indeed the static class Enumerable<T>
contains such kind of functions applicable to anything implementing
IEnumerable<T>). What would be the idiomatic name of such a *class* in
Haskell?
- List ?
- Listable ?
- Enumerable ?
- ListWithContext ?


Giacomo



On Fri, May 31, 2013 at 12:16 PM, mukesh tiwari <
mukeshtiwari.iiitm at gmail.com> wrote:

> Hi Giacomo,
> Data.List can be abstracted using Foldable and Traversable but
> unfortunately I could not find the functions corresponding to head, take.
>
> Prelude Data.Traversable Data.Foldable> :t Data.Foldable.
> Data.Foldable.Foldable    Data.Foldable.concatMap
> Data.Foldable.foldl'      Data.Foldable.foldrM
> Data.Foldable.minimum     Data.Foldable.sequenceA_
> Data.Foldable.all         Data.Foldable.elem
> Data.Foldable.foldl1      Data.Foldable.forM_
> Data.Foldable.minimumBy   Data.Foldable.sequence_
> Data.Foldable.and         Data.Foldable.find
> Data.Foldable.foldlM      Data.Foldable.for_
> Data.Foldable.msum        Data.Foldable.sum
> Data.Foldable.any         Data.Foldable.fold
> Data.Foldable.foldr       Data.Foldable.mapM_
> Data.Foldable.notElem     Data.Foldable.toList
> Data.Foldable.asum        Data.Foldable.foldMap
> Data.Foldable.foldr'      Data.Foldable.maximum
> Data.Foldable.or          Data.Foldable.traverse_
> Data.Foldable.concat      Data.Foldable.foldl
> Data.Foldable.foldr1      Data.Foldable.maximumBy   Data.Foldable.product
> Prelude Data.Traversable Data.Foldable> :t Data.Traversable.
> Data.Traversable.Traversable     Data.Traversable.for
> Data.Traversable.mapAccumR       Data.Traversable.sequenceA
> Data.Traversable.fmapDefault     Data.Traversable.forM
> Data.Traversable.mapM            Data.Traversable.traverse
> Data.Traversable.foldMapDefault  Data.Traversable.mapAccumL
> Data.Traversable.sequence
> Prelude Data.Traversable Data.Foldable> :i Foldable
> class Foldable t where
>   fold :: Data.Monoid.Monoid m => t m -> m
>   foldMap :: Data.Monoid.Monoid m => (a -> m) -> t a -> m
>   Data.Foldable.foldr :: (a -> b -> b) -> b -> t a -> b
>   foldr' :: (a -> b -> b) -> b -> t a -> b
>   Data.Foldable.foldl :: (a -> b -> a) -> a -> t b -> a
>   foldl' :: (a -> b -> a) -> a -> t b -> a
>   Data.Foldable.foldr1 :: (a -> a -> a) -> t a -> a
>   Data.Foldable.foldl1 :: (a -> a -> a) -> t a -> a
>       -- Defined in `Data.Foldable'
> instance Foldable [] -- Defined in `Data.Foldable'
> instance Foldable Maybe -- Defined in `Data.Foldable'
> Prelude Data.Traversable Data.Foldable> :i Tr
> Traversable  True
> Prelude Data.Traversable Data.Foldable> :i Traversable
> class (Functor t, Foldable t) => Traversable t where
>   traverse ::
>     Control.Applicative.Applicative f => (a -> f b) -> t a -> f (t b)
>   sequenceA ::
>     Control.Applicative.Applicative f => t (f a) -> f (t a)
>   Data.Traversable.mapM :: Monad m => (a -> m b) -> t a -> m (t b)
>   Data.Traversable.sequence :: Monad m => t (m a) -> m (t a)
>       -- Defined in `Data.Traversable'
> instance Traversable [] -- Defined in `Data.Traversable'
> instance Traversable Maybe -- Defined in `Data.Traversable'
> Prelude Data.Traversable Data.Foldable> :t foldMap
> foldMap
>   :: (Foldable t, Data.Monoid.Monoid m) => (a -> m) -> t a -> m
>
> -Mukesh
>
>
> On Fri, May 31, 2013 at 2:26 PM, Giacomo Tesio <giacomo at tesio.it> wrote:
>
>> I'm looking for a class abstracting Data.List. I mean something that
>> enable the use of say head, map, take and so on into different kind of
>> types.
>>
>> Is there already something like that?
>>
>>
>> Giacomo
>>
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>
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