Scala Reader Monad Example

/*
 * Scala Reader Monad example from: http://book.realworldhaskell.org/read/monad-transformers.html
 */

def myName(step:String) = for {
    name <- ask[Id, String]
  } yield (step ++ ", I am " ++ name)

def localExample = for {
    a <- myName("First")
    b <- myName("Second").local(_ ++ "dy")
    c <- myName("Third")
  } yield (a,b,c)

localExample runReaderT "Fred" : (String,String,String)
// Res: (String, String, String) = (First, I am Fred,Second, I am Freddy,Third, I am Fred)