お試し inspired by https://qiita.com/mod_poppo/items/03fc14f693b601e0a00f

StateVSIORef.hs

module Bench.StateVSIORef where

import Data.IORef
import Control.Monad.State.Strict


n :: Int
n = 10000 * 10000

rotate :: [a] -> [a]
rotate []     = []
rotate (x:xs) = xs ++ [x]

someCalculationWithState :: IO [Ordering]
someCalculationWithState = flip evalStateT [LT, EQ, GT] $ do
  forM_ [0..n] $ \_ -> do
    modify' rotate
  get

someCalculationWithIORef :: IO [Ordering]
someCalculationWithIORef = do
  accRef <- newIORef [LT, EQ, GT]
  forM_ [0..n] $ \_ -> do
    modifyIORef' accRef rotate
  readIORef accRef

someCalculationWithRec :: IO [Ordering]
someCalculationWithRec = return $ loop 0 [LT, EQ, GT]
  where
    loop i acc
      | i == n    = acc
      | otherwise = loop (i + 1) $ rotate acc