File ‹zippy_action_app_progress.ML›

(*  Title:      Zippy/zippy_action_app_progress.ML
    Author:     Kevin Kappelmann
*)
signature ZIPPY_ACTION_APP_PROGRESS =
sig
  datatype progress = Promising | Unclear
  val promising : progress
  val unclear : progress
  val pretty : progress SpecCheck_Show.show
  val ord : progress ord
end

structure Zippy_Action_App_Progress : ZIPPY_ACTION_APP_PROGRESS =
struct

datatype progress = Promising | Unclear

val promising = Promising
val unclear = Unclear

fun pretty Promising = Pretty.str "Promising"
  | pretty Unclear = Pretty.str "Unclear"

fun ord (Promising, Unclear) = LESS
  | ord (Unclear, Promising) = GREATER
  | ord _ = EQUAL

end