除了Monad之外，在纯函数式语言中还可以使用哪些方式来处理状态？

import Control.Monad.State

-- 定义一个简单的状态
type Counter = Int

-- 增加计数器的函数
increment :: State Counter Counter
increment = do
    current <- get
    put (current + 1)
    return current

-- 使用State Monad运行
runState increment 0

import Control.Monad.Reader

-- 定义一个环境
type Env = String

-- 读取环境变量的函数
readEnv :: Reader Env String
readEnv = ask

-- 使用Reader Monad运行
runReader readEnv "Hello, World!"

main :: IO ()
main = do
    putStrLn "What is your name?"
    name <- getLine
    putStrLn ("Hello, " ++ name ++ "!")

import Control.Monad.ST
import Data.STRef

-- 定义一个简单的状态
type Counter = Int

-- 增加计数器的函数
increment :: STRef s Counter -> ST s Counter
increment ref = do
    current <- readSTRef ref
    writeSTRef ref (current + 1)
    return current

-- 使用ST Monad运行
main :: IO ()
main = do
    ref <- newSTRefIO 0
    let result = runST $ increment ref
    print result

-- 定义一个简单的状态
type Counter = Int

-- 增加计数器的函数
increment :: Counter -> (Counter -> a) -> a
increment current k = k (current + 1)

-- 使用CPS运行
main :: IO ()
main = let initialCounter = 0
           result = increment initialCounter print
       in return ()

import Control.Lens

-- 定义一个简单的数据结构
data Person = Person { _name :: String, _age :: Int } deriving (Show)

-- 定义Lens
nameLens :: Lens' Person String
nameLens = lens _name (\p new -> p { _name = new })

ageLens :: Lens' Person Int
ageLens = lens _age (\p new -> p { _age = new })

-- 使用Lens修改状态
main :: IO ()
main = do
    let person = Person "Alice" 30
    let updatedPerson = person & nameLens .~ "Bob" & ageLens +~ 1
    print updatedPerson