ice-cube

A port of the Ruby ice_cube gem to Haskell.

Usage

ice-cube has a very small API. The date type it uses comes from the Data.Dates package.

import Data.Dates
import IceCube (mkSchedule, occurrences, Rule(..))

Use mkSchedule to create your schedule. mkSchedule takes a start date, an optional end date and a list of recurrence rules.

-- Create a schedule for the 15 of every month,
-- starting on Jan 1st 2017 and ending on Jan 1st 2018
let start = DateTime 2017 1 1 0 0 0
    end = DateTime 2018 1 1 0 0 0
    schedule = mkSchedule start (Just end) [DayOfMonth 15]

-- Create a schedule for the Fridays in February,
-- starting on Jan 1st 2017 and continuing forever
let start = DateTime 2017 1 1 0 0 0
    schedule = mkSchedule start Nothing [DayOfWeek Friday, MonthOfYear 2]

You can pass any number of rules to a schedule to create more complex recurrence patterns.

-- Every two weeks on Friday
[WeeklyInterval 2, DayOfWeek Friday]

-- Every other year on the 12th of March
[YearlyInterval 2, MonthOfYear 3, DayOfMonth 12]

-- Every day
[]

See the documentation for an exhaustive list of rules.

To get the dates for a schedule, use occurrences. If the schedule has no end date, the returned list of dates will be infinite.

let start = DateTime 2017 1 1 0 0 0 -- January 1st 2017
    end = DateTime 2018 1 1 0 0 0   -- January 1st 2018
    schedule = mkSchedule start (Just end) [DayOfMonth 15]
    first_date = take 1 $ occurrences schedule