2013.4.0.0 proposal

Bas van Dijk v.dijk.bas at gmail.com
Tue Nov 12 08:26:57 UTC 2013


On 10 November 2013 22:40, Mark Lentczner <mark.lentczner at gmail.com> wrote:
> Including aeson, which I think we'd all very much like to do, requires
> dlist-0.5.
> Now, dlist has been around for a very long time, and is very stable.
> I do not believe that dlist's API is exposed indirectly via aeson at all.
>
> I hereby propose that it be added to the platform.
> At the very least, it could be like primitive - in the platform, but not
> "part" of it.
>
> Thoughts?

+1

However, note that I don't mind dropping the dlist dependency from
aeson. I use it in a very limited internal place:

https://github.com/bos/aeson/blob/master/Data/Aeson/Types/Generic.hs#L213

Don, If we do decide to include dlist in the HP it would be great if
the following instances can be added to it:

instance Alternative DList where
    empty = empty
    (<|>) = append

instance Eq a => Eq (DList a) where
    (==) = (==) `on` toList

instance Ord a => Ord (DList a) where
    compare = compare `on` toList

instance Show a => Show (DList a) where
    showsPrec p dl = showParen (p >= 10) $
                     showString "Data.DList.fromList " . shows (toList dl)

Bas


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