Something that always struck me as awkward with
foldr is the
b -> f a -> b part of the type signature. So many other useful functions prefer an
a -> b -> b style of signature, like everything operating on Maps, Maybes, ‘modify’ style higher order functions, etc.
I defined in one of my catch-all utility modules the following (the name is not very creative)
foldry :: forall f a b. Foldable f => (a -> b -> b) -> f a -> b -> b foldry = flip <$> foldr
I find that signature reliably more useful and succinct to use. It composes easier, and it’s also good for nested folds.
I was wondering, has anyone else stumbled upon this pattern as well? Or perhaps there is already an knockoff foldr like this published somewhere? I use purescript in relative isolation so I’m curious what others have found.