Re: [Haskell-cafe] Noob error: Type b -> c b Does not match IO a

On Sun, 26 Jun 2005, Daniel Fischer wrote:

...

m x y = if x==0 then 0 else x*y

Plain

foldr m 1

does fine, in fact much better than

foldl' (*) 1 . upTo (== 0),

both in hugs and ghc, regarding speed and memory usage.

E.g. foldr m 1 [a,b,c] means m a (m b (m c 1))) That is, it is not possible for the runtime system to store interim numeric results, it can only accumulate function calls.