Re: [Haskell-cafe] [Q] A typing problem

On Wed, 13 Apr 2005, Didier Verna wrote:

I'm trying to write a function that combines folding and mapping. This function would take two arguments (a folding function and a mapping function), and would return a function of one argument (a list of 'a''s) returning a 'a'.

The idea is to write something like sumsquare = foldmap (+) square

Here's what I write:

foldmap :: (c -> c -> c) -> (c -> c) -> (c -> c -> c) foldmap f m = foldr1 f (map m)

Do you mean foldmap :: (b -> b -> b) -> (a -> b) -> [a] -> b foldmap f m = foldr1 f . map m ?