pseudo inheritance in F#

gistfile1.fs

type Animal = { Name: string; Bark: unit -> string }

let newDog name = { Name = name; Bark = fun _ -> "Bow wow" }
let newCat name = { Name = name; Bark = fun _ -> "meow" }
let newCheetah name = 
  let cat = newCat name
  { Name = name; Bark = cat.Bark >> (fun a -> a + " " + a)}

let dog = newDog "Pochi"
let cat = newCat "Tama"
let cheetah = newCheetah "Hana"

[dog; cat; cheetah] 
|> List.iter (fun animal -> printfn "%A:%A" animal.Name (animal.Bark ()))

// "Pochi":"Bow wow"
// "Tama":"meow"
// "Hana":"meow meow"