Re: Proposal: alpha-rename the type signatures of foldl, foldl', and scanl to be consistent with foldr and scanr

On Sun, Oct 14, 2012 at 09:00:18PM +0200, Gábor Lehel wrote:

On Sun, Oct 14, 2012 at 8:47 PM, Dan Burton wrote:

...

At the risk of useless bikeshedding... might I suggest "r" as a mnemonic for "result"?

foldl :: (a -> r -> r) -> r -> [a] -> r foldr :: (r -> a -> r) -> r -> [a] -> r

-- Dan Burton

'r' is the version I originally used myself (see reddit). But then you have to change the foldrs too, and quite possibly a lot of other functions, and get dragged into a big discussion over when is 'r' a better mnemonic than 'b' and when is it not.

Simply swapping 'a' and 'b' in the left folds captures most of the benefit for least cost.

Same goes for most of the other suggestions I have seen (I don't find the existing signatures actively confusing, merely suboptimal), but if sentiment is overwhelmingly in favor of making further changes I can be swayed. For now I wanted to propose a minimal change with the best chance of attracting a broad consensus.

I'm in favor of the simple change, so +1 ;) Cheers, Simon