DEPRECATED foldWithKey "Use foldrWithKey instead"

Christian Maeder Christian.Maeder at
Thu Dec 9 19:56:39 CET 2010

Hi Johan

Am 09.12.2010 17:54, schrieb Johan Tibell:
> Christian,
> Libraries will change. You will have to update your code. This is
> inevitable unless you want us to freeze everything. If you're still on
> 6.10.4 you need to expect problems soon anyway. Few package authors
> support more than three compiler versions (and many only the one
> they're using themselves).

granted. I appreciate the progress to better libraries (and your
personal contributions).

> If you want to hold off upgrading your code you can put an upper bound
> on the package dependency in the Cabal file (you should do that
> anyway).

I surely do want to upgrade.

> If someone changes something, assume that they do so for a reason.
> Don't so yelling on the list that someone should change it back just
> because you say to. Ask: "I see that X changed. I'm curious about the
> reason. Personally, it gives me problem Z and I would like to know if
> having Z is necessary."

I did not mean to "yell", in fact, I asked.
I wasn't curious about the reason, because the reason looked obvious to me:
  - avoid different names for the same thing
  - orthogonality to the prelude (foldl and foldr and no fold)

The counter-arguments:
  - orthogonality to Data.IntMap is lost
  - there are other different names for the same thing (like toList)
  - intents to destroy backwards compatibility (for weak reasons)
  - may distract from more important deprecation warnings

> Working with the libraries process is annoying enough as it is that I
> don't really feel like also having to deal with people second guessing
> all the decisions we make.

Why is it a problem to regret a decision being made? Is it such a big
deal to remove (or keep) a deprecation warning? If this is the case,
maybe someone (more patiently) wants to go ahead.

Cheers Christian

> Johan

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