git.iko.soy/rowtype-yoga/purescript-native
on e82e607 help sign in
rowtype-yoga/purescript-native/examples/passing/Collatz.purs
18 lines 388 B history raw
1module Main where
3import Prelude
4import Control.Monad.Eff
5import Control.Monad.ST
7collatz :: Number -> Number
8collatz n = runPure (runST (do
9 r <- newSTRef n
10 count <- newSTRef 0
11 untilE $ do
12 modifySTRef count $ (+) 1
13 m <- readSTRef r
14 writeSTRef r $ if m % 2 == 0 then m / 2 else 3 * m + 1
15 return $ m == 1
16 readSTRef count))
18main = Debug.Trace.print $ collatz 1000