nominal epoch_42 = ()
nominal fresh = ()
nominal expired = ()
nominal draft = ()
nominal authorized = ()

union clock epoch =
    | Clock42 :: clock epoch_42

union deadline epoch status =
    | FreshDeadline :: deadline epoch_42 fresh
    | ExpiredDeadline :: deadline epoch_42 expired

union document epoch state =
    | DraftDocument :: document epoch_42 draft
    | AuthorizedDocument :: document epoch_42 authorized

inl authorize forall epoch.
    (clock : clock epoch)
    (deadline : deadline epoch fresh)
    (document : document epoch draft)
    : document epoch authorized =
    match clock, deadline, document with
    | Clock42, FreshDeadline, DraftDocument => AuthorizedDocument

inl render (document : document epoch_42 authorized) : string =
    match document with
    | AuthorizedDocument => "deadline-witness"

inl main () : string =
    render (authorize Clock42 FreshDeadline DraftDocument)