Обьяснить работу кода макcимально подробно

data Pers = Pers{ name :: String, boss :: String }
            deriving (Eq,Show)
type Plist = [Pers]
 
getOne :: Plist -> Pers
getOne([]) = Pers { name = "",  boss = ""}
getOne(l) = l !! 0
 
getByName :: Plist -> String -> Pers
getByName list pers = getOne $ filter (\x -> (name x) == pers) list
 
getNames :: Plist->[String]
getNames list = [ name x | x <- list ]
 
getBoss :: Plist -> String -> String
getBoss list pers = boss (getByName list pers)
 
getSubordinate :: Plist -> String -> Plist
getSubordinate list pers = filter (\x -> (boss x) == pers) list
 
getAllSub :: Plist->String->[String]->Plist
getAllSub list pers names =
    concat [(getAllSubordinate list x) | x<-names]
 
getAllSubordinate :: Plist->String->Plist
getAllSubordinate list pers =
    sub ++ (getAllSub list pers (getNames sub))
    where
        sub = getSubordinate list pers
 
 
getList :: Plist -> [(String,Int)]
getList list = [((name x),
                length $ (getAllSubordinate list (name x))) | x <- list]
 
person :: String->String -> Pers
person n b = Pers {name = n, boss = b}
 
main :: IO()
main = do
    let list = [(person "x" ""),
                (person "y" "x"),
                (person "z" "y"),
                (person "w" "x")]
    print $ getNames $ getAllSubordinate list "x"