Module Timere

Date time reasoning

Timere provides a set of highly expressive APIs to describe scheduling constraints, and an efficient resolution algorithm

type timestamp = Timedesc.timestamp
type t

This is the core type of Timere that represents sets of points in time, more precisely, unions of time intervals. For example, "all Mondays of year 2000 at the UTC timezone".

We call Timere.t values "timere object"; internally they are rich expressions representing the time computations (union, intersection, etc.), lazily forced into more low-level descriptions (lazy sequences of intervals).

type inc_exc = [
| `Inc
| `Exc
]
type 'a range = [
| `Range_inc of 'a * 'a
| `Range_exc of 'a * 'a
]

Basic constructors

val now : unit -> t

Time right now

val always : t

Entire interval that Timere can handle, i.e. [0000 Jan 01 14:00:00 +00:00:00, 9999 Dec 31 09:59:58 +00:00:00)

val empty : t

Empty interval

val before : Timedesc.t -> t
val since : Timedesc.t -> t
val after : Timedesc.t -> t
val date_time : Timedesc.t -> t
val date_times : Timedesc.t list -> t
val date_time_seq : Timedesc.t Stdlib.Seq.t -> t
val sorted_date_times : Timedesc.t list -> t
val sorted_date_time_seq : Timedesc.t Stdlib.Seq.t -> t
exception Invalid_timestamp
val timestamp : Timedesc.timestamp -> t
val before_timestamp : Timedesc.timestamp -> t
val since_timestamp : Timedesc.timestamp -> t
val after_timestamp : Timedesc.timestamp -> t
val timestamps : ?skip_invalid:bool -> Timedesc.timestamp list -> t

timestamps l

skip_invalid defaults to false

  • raises Invalid_timestamp

    if not skip_invalid and l contains an invalid timestamp

val timestamp_seq : ?skip_invalid:bool -> timestamp Stdlib.Seq.t -> t

timestamps s

skip_invalid defaults to false

  • raises Invalid_timestamp

    if not skip_invalid and s contains an invalid timestamp

val sorted_timestamps : ?skip_invalid:bool -> timestamp list -> t
val sorted_timestamp_seq : ?skip_invalid:bool -> timestamp Stdlib.Seq.t -> t

Pattern matching constructors

val pattern : ?years:int list -> ?year_ranges:int range list -> ?months:int list -> ?month_ranges:int range list -> ?days:int list -> ?day_ranges:int range list -> ?weekdays:Timedesc.weekday list -> ?weekday_ranges:Timedesc.weekday range list -> ?hours:int list -> ?hour_ranges:int range list -> ?minutes:int list -> ?minute_ranges:int range list -> ?seconds:int list -> ?second_ranges:int range list -> ?ns:int list -> ?ns_ranges:int range list -> unit -> t

Pattern matches over date times.

A pattern p matches date time dt if

(year of dt is in p.years or p.year_ranges)
&& (month of dt is in p.months or p.month_ranges)
&& (month day of dt is in p.month_days or p.month_day_ranges)
&& (weekday of dt is in p.weekdays or p.weekday_ranges)
&& (hour of dt is in p.hours or p.hour_ranges)
&& (minute of dt is in p.minutes or p.minute_ranges)
&& (second of dt is in p.seconds or p.second_ranges)
&& (ns of dt is in p.ns or p.ns_ranges)

Empty pattern levels are treated as wildcard, e.g. if p.years and p.year_ranges are both empty, then (dt.year is in p.years or p.year_ranges) is true.

val iso_week_pattern : ?years:int list -> ?year_ranges:int range list -> ?weeks:int list -> ?week_ranges:int range list -> unit -> t

Pattern matches over ISO week date times.

A pattern p matches ISO week date time dt if

(year of dt is in p.years or p.year_ranges)
&& (week of dt is in p.weeks or p.week_ranges)

Empty pattern levels are treated as wildcard, e.g. if p.years and p.year_ranges are both empty, then (dt.year is in p.years or p.year_ranges) is true.

val years : int list -> t

years l is a shorthand for pattern ~years:l ()

val year_ranges : int range list -> t

year_ranges l is a shorthand for pattern ~year_ranges:l ()

val iso_years : int list -> t

iso_years l is a shorthand for iso_week_pattern ~years:l ()

val iso_year_ranges : int range list -> t

iso_year_ranges l is a shorthand for iso_week_pattern ~year_ranges:l ()

val months : int list -> t

months l is a shorthand for pattern ~months:l ()

val month_ranges : int range list -> t

month_ranges l is a shorthand for pattern ~month_ranges:l ()

val iso_weeks : int list -> t

iso_weeks l is a shorthand for iso_week_pattern ~weeks:l ()

val iso_week_ranges : int range list -> t

iso_week_ranges l is a shorthand for iso_week_pattern ~week_ranges:l ()

val days : int list -> t

days l is a shorthand for pattern ~month_days:l ()

val day_ranges : int range list -> t

day_ranges l is a shorthand for pattern ~month_day_ranges:l ()

val weekdays : Timedesc.weekday list -> t

weekdays l is a shorthand for pattern ~weekdays:l ()

val weekday_ranges : Timedesc.weekday range list -> t

weekday_ranges l is a shorthand for pattern ~weekday_ranges:l ()

val hours : int list -> t

hours l is a shorthand for pattern ~hours:l ()

val hour_ranges : int range list -> t

hour_ranges l is a shorthand for pattern ~hour_ranges:l ()

val minutes : int list -> t

minutes l is a shorthand for pattern ~minutes:l ()

val minute_ranges : int range list -> t

minute_ranges l is a shorthand for pattern ~minute_ranges:l ()

val seconds : int list -> t

seconds l is a shorthand for pattern ~seconds:l ()

val second_ranges : int range list -> t

second_ranges l is a shorthand for pattern ~second_ranges:l ()

val ns : int list -> t

ns l is a shorthand for pattern ~ns:l ()

val ns_ranges : int range list -> t

ns_ranges l is a shorthand for pattern ~ns_ranges:l ()

val nth_weekday_of_month : int -> Timedesc.weekday -> t

nth_weekday_of_month n wday picks the nth weekday of all months, where 1 <= n && n <= 5

  • raises Invalid_argument

    if n is out of range

Intervals

Explicit intervals

exception Interval_is_invalid
exception Intervals_are_not_sorted
val intervals : ?skip_invalid:bool -> Timedesc.Interval.t list -> t

intervals l

skip_invalid defaults to false

  • raises Interval_is_invalid

    if not skip_invalid and l contains an invalid interval

val interval_seq : ?skip_invalid:bool -> Timedesc.Interval.t Stdlib.Seq.t -> t

interval_seq s

skip_invalid defaults to false

  • raises Interval_is_invalid

    if not skip_invalid and s contains an invalid interval

val sorted_intervals : ?skip_invalid:bool -> Timedesc.Interval.t list -> t

sorted_intervals l

skip_invalid defaults to false

  • raises Interval_is_invalid

    if not skip_invalid and l contains an invalid interval

  • raises Intervals_are_not_sorted

    if l is not sorted

val sorted_interval_seq : ?skip_invalid:bool -> Timedesc.Interval.t Stdlib.Seq.t -> t

sorted_interval_seq s

skip_invalid defaults to false

  • raises Interval_is_invalid

    if not skip_invalid and s contains an invalid interval

  • raises Intervals_are_not_sorted

    if s is not sorted

Pattern matching intervals

Pattern matching intervals are designed to handle intervals where start and end points follow some pattern, but cannot be captured by pattern efficiently, e.g. you cannot represent "5:30pm to 6:11pm" via a single pattern

module Points : sig ... end
type points = Points.t
val pattern_intervals : ?inc_exc:inc_exc -> ?bound:Timedesc.Span.t -> [ `Whole | `Fst | `Snd ] -> points -> points -> t

pattern_intervals mode p1 p2 for each point x matched by p1, then for the earliest point y matched by p2 such that x < y && y - x <= bound

  • if mode = `Whole && inc_exc = `Exc, yields (x, y)
  • if mode = `Whole && inc_exc = `Inc, yields (x, y + 1)
  • if mode = `Fst, yields (x, x + 1)
  • if mode = `Snd, yields (y, y + 1)

above implies inc_exc does not impact operations if mode is `Fst or `Snd.

inc_exc defaults to `Exc.

Default bound is inferred as follows, and should suffice in yielding desired results for most cases:

if p2 is YMDHMS then (year of p2 - year of p1 + 1) * 366 days
if p2 is  MDHMS then 366 days
if p2 is   DHMS then
  if day of p1 < day of p2 then 31 - day of p2 days
  else                                      31 days
if p2 is    HMS then  30 hours
if p2 is     MS then   1 hours
if p2 is      S then   1 minutes

where we say p2 is YMDHMS if p2 = Points.make_exn ~year:_ ... () and so on.

Examples:

pattern_intervals `Whole
  (Points.make ~hour:13 ~minute:0 ~second:0 ()) (* p1 *)
  (Points.make ~hour:14 ~minute:0 ~second:0 ()) (* p2 *)

yields all the "1pm to 2pm" intervals, since at each "1pm" mark represented by p1, searching forward up to 24 hour period, we can find a "2pm" mark in p2

pattern_intervals `Whole
  (Points.make ~month:2 ~day:10 ~hour:13 ~minute:0 ~second:0 ()) (* p1 *)
  (Points.make                  ~hour:14 ~minute:0 ~second:0 ()) (* p2 *)

yields all the "Feb 10th 1pm to 2pm" intervals (or specifically "Feb 10th 1pm to Feb 10th 2pm")

pattern_intervals `Whole
  (Points.make ~month:`Feb ~day:10 ~hour:23 ~minute:0 ~second:0 ()) (* p1 *)
  (Points.make                     ~hour:3  ~minute:0 ~second:0 ()) (* p2 *)

yields all the "Feb 10th 11pm to 3am" intervals (or specifically "Feb 10th 11pm to Feb 11th 3am")

  • raises Invalid_argument

    if bound is negative

  • raises Invalid_argument

    if precision (number of date time arguments passed to make_points during construction) of p1 < precision of p2

    For example, Points.make_exn ~hour:3 ~minute:0 ~second:0 () has a lower precision than make_points_exn ~day:10 ~hour:12 ~minute:30 ~second:0 ().

Hour minute second intervals

Convenience wrappers around points and pattern_intervals

val hms_intervals : ?inc_exc:inc_exc -> Timedesc.Time.t -> Timedesc.Time.t -> t

Same as pattern_intervals ... with bound fixed to Span.For_human.make ~days:1 ()

inc_exc defaults to `Exc

Algebraic operations

val inter : t list -> t

Intersection of list of timeres.

inter [] is equivalent to always.

val union : t list -> t

Union of list of timeres.

union [] is equivalent to empty.

val not : t -> t

Negation of timere.

not t is equivalent to all the intervals not included in t.

val shift : Timedesc.Span.t -> t -> t
val lengthen : Timedesc.Span.t -> t -> t
  • raises Invalid_argument

    if duration is negative

val with_tz : Timedesc.Time_zone.t -> t -> t

with_tz tz t changes the time zone to evaluate t in to tz

Chunking

type chunked
type chunking = [
| `Disjoint_intervals
| `By_duration of Timedesc.Span.t
| `By_duration_drop_partial of Timedesc.Span.t
| `At_year_boundary
| `At_month_boundary
]

Ways to chunk/slice time intervals for the selector.

  • `Disjoint_intervals gives a sequence of disjoint intervals to the selector, specifically they are in ascending order, non-overlapping, non-connecting, and unique
  • `By_duration slices in the fixed size specified by the duration. Partial chunks (chunks less than the fixed size) are preserved.
  • `By_duration_drop_partial slices in the fixed size specified by the duration. Partial chunks (chunks less than the fixed size) are discarded.
  • `At_year_boundary slices at the year boundary (e.g. 2021 Jan 1st 00:00:00)
  • `At_month_boundary slices at the month boundary (e.g. Aug 1st 00:00:00)
val chunk : chunking -> ( chunked -> chunked ) -> t -> t

chunk chunking f t applies chunked selector f on t.

  • raises Invalid_argument

    if duration is negative in `By_duration or `By_duration_drop_partial

Chunked selectors

You may find (%>) useful for chaining selectors together, e.g. drop 5 %> take 2

val chunk_again : chunking -> chunked -> chunked

chunk_again chunking f applies chunked selector f as a selector

val first : chunked -> chunked

Takes only first chunk

val take : int -> chunked -> chunked

Takes n chunks

val take_nth : int -> chunked -> chunked

Take every nth chunk, specifically 0th, nth, 2nth, 3nth, ...

val drop : int -> chunked -> chunked

Discard n chunks

Infix operators

val (&&&) : t -> t -> t
val (|||) : t -> t -> t
val (%>) : ( 'a -> 'b ) -> ( 'b -> 'c ) -> 'a -> 'c

Composition, mainly for chunked selectors

f1 %> f2 is equivalent to fun x -> x |> f1 |> f2.

Resolution

val resolve : ?search_using_tz:Timedesc.Time_zone.t -> t -> ( Timedesc.Interval.t Stdlib.Seq.t, string ) Stdlib.result

Resolves a Timere object into a concrete interval sequence. * * Intervals are left-closed, right-open, i.e. each interval is * of the form [x, y), which includes x and excludes y. *

exception Resolution_error of string
val resolve_exn : ?search_using_tz:Timedesc.Time_zone.t -> t -> Timedesc.Interval.t Stdlib.Seq.t
  • raises Resolution_error

    if resolve fails

S-expressions

These functions are suitable for debugging, serializing and deserializing timeres.

The sexp is a precise description of the steps used to construct a timere. As such deserialization is accurate and goes through the exact same construction steps (including validation) as one would using the construction API directly.

val to_sexp : t -> Sexplib.Sexp.t
val to_sexp_string : t -> string
val of_sexp : Sexplib.Sexp.t -> ( t, string ) Stdlib.result
val of_sexp_string : string -> ( t, string ) Stdlib.result
val pp_sexp : Stdlib.Format.formatter -> t -> unit

Misc

module Utils : sig ... end