ExampleReader.hs

module ExampleReader where

import Control.Monad.Reader

data Person = Pr { name    :: String,
                   age     :: Integer,
                   address :: String }
                   
type PersonReader = Reader Person String
                   
getName :: PersonReader
getName = do
    n <- ask
    return $ "Name: " ++ name n
    
getAge :: PersonReader
getAge = do
    n <- ask
    return $ "Age: " ++ (show (age n))
    
getAddress :: PersonReader
getAddress = do
    n <- ask
    return $ "Address: " ++ address n
                   
showPerson :: PersonReader
showPerson = do
    x <- getName
    y <- getAge
    z <- getAddress
    return . unlines $ [x, y, z]

main = putStrLn $ runReader showPerson $ (Pr "David" 32 "Casa meva")