Protype-base "subclassing" with immutable records

FunctionRecord.fr

module FunctionRecord where

data FRecord    = FRecord {
    parent      :: FRecord,
    name        :: String,
    toString    :: (FRecord ->  String)
}

prototype = FRecord   { parent = prototype, name = undefined, toString = (\r -> r.name) }
dierk     = prototype.{ name = "Dierk" }
phil      = prototype.{ name = "Phil", toString = (\r -> "Wadler") }

main _ = do
    println $ prototype.toString dierk  -- Dierk
    println $ prototype.toString phil   -- Phil   (prototype  toString)
    println $ phil.toString phil        -- Wadler (overridden toString)
    println $ phil.parent.toString phil -- Phil   (parent     toString)