Haskell Survik 'oop'

{-# LANGUAGE RecordWildCards #-}

module Main where

import Control.Monad.State

data Item = Item {

name :: String,

description :: String,

useTime :: Int,

useCount :: Int

}

type TotalItemsCreated = Int

useItem :: Item -> State TotalItemsCreated String

useItem item@Item{..} = do

modify (+1)

return $ "Používá se " ++ name ++ " (" ++ description ++ "), což trvá " ++ show useTime ++ " sekund. Počet použití: " ++ show (useCount + 1)

data Survik = Survik {

survikName :: String,

item :: Item

}

useSurvikItem :: Survik -> State TotalItemsCreated String

useSurvikItem Survik{..} = do

itemLine <- useItem item

return $ survikName ++ " používá " ++ name item ++ ": " ++ itemLine

main :: IO ()

main = do

let baterka = Item "Baterka" "osvětluje cestu" 0 0

lekarnicka = Item "Lékárnička" "léčí zranění" 20 0

pepa = Survik "Pepik the survik" baterka

let (result, totalItems) = runState (useSurvikItem pepa >> useSurvikItem (pepa { item = lekarnicka })) 0

putStrLn result

print totalItems