empty clashes with Control.Applicative about basic-prelude HOT 5 CLOSED

A simple sollution is using identity instead of empty like in:

import BasicPrelude hiding (empty)
import Control.Applicative (Alternative(..))
identity = mempty

It would be nice if this would be fixed in BasicPrelude itself!

from basic-prelude.

I'm quite happy with the current situation: the vast majority of packages use the term empty to mean mempty (bytestring, text, vector, containers, unordered-containers) and our goal is to fit the common use cases. I think Alternative is far less often used, and certainly its empty member even less so. I'd be happy to provide some export such as aempty = Control.Applicative.empty. For declaring instances, the conflict doesn't cause problems:

import Control.Applicative
import BasicPrelude
import Prelude ()

data Foo a

instance Applicative Foo where
    pure = undefined
    (<*>) = undefined

instance Functor Foo where
    fmap = undefined

instance Alternative Foo where
    empty = undefined
    (<|>) = undefined

from basic-prelude.

If it doesn't affect instance declaration -- I didn't know -- I totally agree with you. I think bare would be a nice synonym for Alternatvie.empty. The name is not used in most libraries (http://www.haskell.org/hoogle/?hoogle=bare), whereas void for instance is already taken. Alternative is used a lot in combination with parsers. Although most users only use Alternative.<|> and Alternative.many, I think it is nice to have access to it.

from basic-prelude.

I vote for aempty, but I'm also ok with identity

from basic-prelude.

I have a hard time seeing the Right Way for us to handle this issue, so I would trust @snoyberg's intuition on this one. As I understand it, the Maybe Monoid instance is the only thing to be concerned about. If we choose to export a synonym for Alternative.empty, it should not be identity, a valuable name that is way too general for Alternative to deserve.

from basic-prelude.