Re: Proposal: keep Data.Map.foldWithKey

Am 14.01.2011 11:13, schrieb Gregory Collins:

On Fri, Jan 14, 2011 at 8:56 AM, Sittampalam, Ganesh wrote:

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This isn't aimed at you specifically, but I suggest that if someone objects to a proposal on the grounds that an alternative route is better, they should actually propose that so that we can have a proper debate between the alternatives.

I agree. Patch attached.

This patch + , foldlWithKey + , foldrWithKey + , foldlWithKey' + , foldrWithKey' is definitely a much bigger API change (than removing a deprecation) that should only be applied for a new major release. I support these additions but it is not part of my proposal.

Side note: there are tons of long lines and lines with dangling whitespace in these files. It could use a cleanup. I also fixed the docstrings for Data.Map.foldlWithKey and Data.Map.foldrWithKey.

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Removing foldWithKey from IntMap would (arguably) require foldrWithKey and foldlWithKey to be exposed instead. It seems Milan raised this in http://www.haskell.org/pipermail/libraries/2010-September/014410.html and there was no objection, but nothing further was done.

So symmetry (assuming one agrees it's so important to have it in the first place) is still broken anyways if we roll back the "foldWithKey" deprecation?

Yes, the symmetry is still broken because "foldWithKey" will be deprecated in Data.Map but not in Data.IntMap, yet. If Data.IntMap.foldWithKey is immediately deprecated, too, and users follow this deprecation advice they can no longer compile their sources with "older" compiler (where "old" means ghc-7.0.1). C.