Hi everybody,

it's my first message on this ML :)

I don't know if it's appropriate to post this here but I would like to have some feedback with one of my first Haskell code.

I've been inspired by a recent Numberphile video (https://www.youtube.com/watch?v=HJ_PP5rqLg0) how explain the "Russian Peasant" algorithm to do multiplication (here in a nutshell : https://www.wikihow.com/Multiply-Using-the-Russian-Peasant-Method)

So I decided I give it a go in Haskell, here is my solution, I appreciate if you give me some feedback on how to improve this code (make it more "idiomatic Haskell")

NB : I apologize if it's not the right place to ask this kind of review ... in that case, where can I post this ?

Thanks !

module DivRusse where

main :: IO ()
main = do
    putStrLn "13 x 12 is"
    print $ russmul 13 12

russmul :: Int -> Int -> Int
russmul a b  =
    let filteredPair = filter (\pair -> (fst pair) `mod` 2 /= 0 ) $ (a,b) : russmulList a b
    in foldr (\pair acc -> snd pair + acc) 0 filteredPair


russmulList :: Int -> Int -> [(Int, Int)]
russmulList 1 _ = []
russmulList a b =
    let a' = a `div` 2
        b' = b * 2
    in  (a', b') : russmulList a' b'