Experiments with F#

structs.fsx

// F# equivalent of ML signatures?
type MSIG =
  interface
    // Cannot embed type signatures.
    //type key
    abstract x : int
  end

// F# equivalent of ML structures?
type M =
  struct
    // Cannot embed type signatures.
    //type key = string
    val x : int
    private new(value) = { x = value }
    interface MSIG with
        member this.x = this.x
    static member instance = M(1)
  end

printfn "M.instance.x = %A" M.instance.x

// Another attempt using a class hardly helps
type M' private () =
  class
    static let x = 1
    static member instance = M'()
    interface MSIG with
        member this.x = x
  end

// Essentially, modules and their .fsi signature files
// make up F#'s support for signatures and structures,
// where modules are non-parameterized structures.
module M'' =
    let x = 1