Counters are initialized every time?

Question

I try to make a simple counter. My counters do not go up however. It seems to me as if they are re-initialized every time by the function \"inc\" or maybe the (n+1) does not

Answer 1

Just like in code outside of IO, you can string together a series of computations using a fold. foldM operates within a monad, e.g.

main = do
    conn <- connect "192.168.35.62" 8081
    let tryOnePing (c, f) i = do
        p <- ping conn "ping"
        return $ if p == "pong" then (c+1, f) else (c, f+1)
    (c, f) <- foldM tryOnePing (0, 0) [0 .. 10000]
    print (c, f)