Generalize "set" operations from Data.List

[Vanessa McHale]

Isn't deleteBy achievable via a filter?

On 10/31/18 10:03 PM, Dannyu NDos wrote:
> It would be more ineffecient if I had to convert my lists to Data.Sets
> ot Data.Maps every time... For small lists, the operations are simple
> and practical. This doesn't have anything with generalization of type
> signatures anyway.
>
> 2018년 11월 1일 (목) 11:58에 David Feuer <david.feuer at gmail.com
> <mailto:david.feuer at gmail.com>>님이 작성:
>
>     I don't think it's really so great that Data.List has a bunch of
>     operations that are inefficient on lists.
>
>     On Wed, Oct 31, 2018, 10:53 PM Dannyu NDos <ndospark320 at gmail.com
>     <mailto:ndospark320 at gmail.com> wrote:
>
>         I've suffered from inconvenience due to the restricted type
>         signature. I'll be very glad if such restrictions are lifted:
>
>         deleteBy :: (a -> b -> Bool
>         <http://hackage.haskell.org/package/base-4.12.0.0/docs/Data-Bool.html#t:Bool>)
>         -> a -> [b] -> [b]
>         deleteFirstsBy :: (a -> b -> Bool
>         <http://hackage.haskell.org/package/base-4.12.0.0/docs/Data-Bool.html#t:Bool>)
>         -> [a] -> [b] -> [b]
>         intersectBy :: (a -> b -> Bool
>         <http://hackage.haskell.org/package/base-4.12.0.0/docs/Data-Bool.html#t:Bool>)
>         -> [a] -> [b] -> [a]
>
>         I approve these versions because:
>         1. It makes more sense that the "usual" `delete` and
>         `intersect` functions are specialization of the "By"
>         operations, not the vice versa.
>         2. Data.Map.Lazy module from *containers* package has these
>         kind of "By" operations.
>
>         The previous discussion about this in Sep 2016 didn't make
>         much conclusion, so let the discussion continue.
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