module type S =
  sig
    type t
    type day = Sun | Mon | Tue | Wed | Thu | Fri | Sat
    type month =
        Jan
      | Feb
      | Mar
      | Apr
      | May
      | Jun
      | Jul
      | Aug
      | Sep
      | Oct
      | Nov
      | Dec
    type year = int
    type field = [ `Day | `Month | `Week | `Year ]
    exception Out_of_bounds
    exception Undefined
    val make : year -> int -> int -> t
    val lmake : year:year -> ?month:int -> ?day:int -> unit -> t
    val today : unit -> t
    val from_jd : int -> t
    val from_mjd : int -> t
    val from_day_of_year : year -> int -> t
    val days_in_month : t -> int
    val day_of_week : t -> day
    val day_of_month : t -> int
    val day_of_year : t -> int
    val week : t -> int
    val month : t -> month
    val year : t -> year
    val to_jd : t -> int
    val to_mjd : t -> int
    val equal : t -> t -> bool
    val compare : t -> t -> int
    val hash : t -> int
    val is_valid_date : year -> int -> int -> bool
    val is_leap_day : t -> bool
    val is_gregorian : t -> bool
    val is_julian : t -> bool
    val to_unixtm : t -> Unix.tm
    val from_unixtm : Unix.tm -> t
    val to_unixfloat : t -> float
    val from_unixfloat : float -> t
    val to_business : t -> year * int * day
    val from_business : year -> int -> day -> t
    val int_of_day : day -> int
    val day_of_int : int -> day
    val int_of_month : month -> int
    val month_of_int : int -> month
    module Period :
      sig
        type t
        val empty : t
        val add : t -> t -> t
        val sub : t -> t -> t
        val opp : t -> t
        val equal : t -> t -> bool
        val compare : t -> t -> int
        val hash : t -> int
        val make : int -> int -> int -> t
        val lmake : ?year:int -> ?month:int -> ?day:int -> unit -> t
        val year : int -> t
        val month : int -> t
        val week : int -> t
        val day : int -> t
        exception Not_computable
        val nb_days : t -> int
        val ymd : t -> int * int * int
      end
    val add : t -> Period.t -> t
    val sub : t -> t -> Period.t
    val rem : t -> Period.t -> t
    val next : t -> field -> t
    val prev : t -> field -> t
    val is_leap_year : year -> bool
    val same_calendar : year -> year -> bool
    val days_in_year : ?month:month -> year -> int
    val weeks_in_year : year -> int
    val week_first_last : int -> year -> t * t
    val nth_weekday_of_month : year -> month -> day -> int -> t
    val century : year -> int
    val millenium : year -> int
    val solar_number : year -> int
    val indiction : year -> int
    val golden_number : year -> int
    val epact : year -> int
    val easter : year -> t
    val carnaval : year -> t
    val mardi_gras : year -> t
    val ash : year -> t
    val palm : year -> t
    val easter_friday : year -> t
    val easter_saturday : year -> t
    val easter_monday : year -> t
    val ascension : year -> t
    val withsunday : year -> t
    val withmonday : year -> t
    val corpus_christi : year -> t
  end