Re: Proposal: Add a strict version of foldlWithKey to Data.Map

On Sun, Aug 22, 2010 at 09:45:32AM +0200, Johan Tibell wrote:

On Sat, Aug 21, 2010 at 1:45 PM, Ian Lynagh wrote:

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On Wed, Aug 18, 2010 at 02:00:39PM +0200, Johan Tibell wrote:

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The current API doesn't offer any efficient way to do something simple as e.g. summing the values in a map. I suggest we add a foldlWithKey'

function:

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http://hackage.haskell.org/trac/ghc/ticket/4261

Shouldn't (go z l) be forced too?

It makes sense to me to do so but the core looks worse for some reason:

Well, if there's a GHC code performance bug then we should fix it, but I don't think we should use a workaround in the libraries that gives a function the wrong strictness.

which doesn't have an unboxed accumulator. I'm not sure why.

Can you file a GHC ticket with a standalone testcase please? Thanks Ian