Discussion: lookups in maps

[Oliver Charles]

Could you share why you are more enthusiastic about such a function?

On Mon, 8 Jun 2020, at 8:07 PM, David Feuer wrote:
> Discussion has gotten going again about harmonizing between the names findWithDefault and lookupDefault in containers and unordered-containers:
> 
>  findWithDefault :: Ord k
>  => a -> k -> Map k a -> a
>  lookupDefault :: (Eq k, Hashable k)
>  => a -> k -> HashMap k a -> a
> 
> I've been fairly unenthusiastic about adding extra names for this function in one package or the other, in large part because I don't like the function. I'd much rather have something in the spirit of `either`, `maybe`, `bool`, etc.:
> 
>  lurkup :: Ord k
>  => r -> (a -> r) -> k -> Map k a -> r
>  lurkup r f k = maybe r f . lookup k
>  lookup k = lurkup Nothing Just k
> 
> Unfortunately, I haven't been able to come up with a decent name for this function. Can anyone help?
> _______________________________________________
> Libraries mailing list
> Libraries at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
> 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/libraries/attachments/20200608/873c9186/attachment.html>