ex_cldr_calendars

# Changelog for Cldr Calendars v1.11.0-rc.0

This is the changelog for Cldr Calendars v1.11.0-rc.0 released on October 27th, 2020.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Add support for [CLDR 38](http://cldr.unicode.org/index/downloads/cldr-38)

# Changelog for Cldr Calendars v1.10.1

This is the changelog for Cldr Calendars v1.10.1 released on September 26th, 2020.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Bug Fixes

* Add a shim for `default_backend/0` that delegates to `Cldr.default_backend/0` or `Cldr.default_backend!/0` depending on `ex_cldr` release. Releases from `2.18.0` use `Cldr.default_backend!/0`.

# Changelog for Cldr Calendars v1.10.0

This is the changelog for Cldr Calendars v1.10.0 released on August 29th, 2020.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Supports upcoming Elixir 1.11.0.  The `Calendar` callback for `day_of_week/3` has been changed to `day_of_week/4` to allow for a different start day of week.  Since `Cldr Calendars` already supports defining calendars with different start days of the week (ie other than Monday), the impementation only supports the `:default` parameter. Thanks to @lostkobrakai for the report. Closes `Cldr Dates Times` issue #17.

# Changelog for Cldr Calendars v1.9.0

This is the changelog for Cldr Calendars v1.9.0 released on June 7th, 2020.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Add `Cldr.Calendar.plus/{3,4}` that allows adding a `Cldr.Calendar.Duration` to a `Calendar.date`. Support for adding durations to `datetime`s is not yet available.

* Add support for `datetimes` to `Cldr.Calendar.Duration.new/2`

* Add support for `Date.Range.t` and `CalendarInterval.t` to `Cldr.Calendar.Duration.new/1`

### Bug Fixes

* More complete test coverage on durations with some additional corner case fixes

# Changelog for Cldr Calendars v1.8.1

This is the changelog for Cldr Calendars v1.8.1 released on June 4th, 2020.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Bug Fixes

* Fix duration calculation when the year and month are the same and the day of the last date is greater than the day of the first date

# Changelog for Cldr Calendars v1.8.0

This is the changelog for Cldr Calendars v1.8.0 released on May 4th, 2020.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Breaking Change (that you might notice but probably won't)

* The `min_days_in_first_week` for the calendar `Cldr.Calendar.Gregorian` is changed to be `1` rather than the previous value of `4`. This only affects week-related processing for the calendar. The reason for the change is that the majority of territories have a preference for `1` for `min_days_in_first_week` so `Cldr.Calendar.Gregorian` more closely aligns to majority expectations.

### Breaking changes (that you shouldn't notice)

* The return result from `Cldr.Calendar.new/3` may return `{:module_already_exists, module}`. It previously returned `{:already_exists, module}`

### Bug Fixes

* Use `backend.get_locale/0` instead of `Cldr.get_locale/0` for all options

* Ensure that the default values for a locale's `min_days` and `first_day_of_week` are correctly applied in `Cldr.Calendar.new/3`. Any values passed as options take precedence over those defined for a locale.

### Enhancements

* Add `Cldr.Calendar.calendar_for_locale/2` which will create (or return) a gregorian-based calendar configured for the supplied locale. This typically means applying the correct values for `min_days` and `first_day_of_week`. For now all calendars created in this way are Gregorian monthly calendars.

* Add `Cldr.Calendar.Preference.calendar_for_locale/1` which returns the appropriate calendar for a locale based upon locale preferences and configured calendars. Unlike `Cldr.Calendar.calendar_for_locale/2`, this function may return non-Gregorian calendars. For example, for the locale `fa-IR` it will return `Cldr.Calendar.Persian` (if [ex_cldr_calendars_persian](https://hex.pm/packages/ex_cldr_calendars_persian) is configured) because that is the locale preference.

* Add `Cldr.Calendar.Preference.calendar_for_territory/1` provides the same result as `Cldr.Calendar.Preference.calendar_for_locale/2` except that argument is a territory code.

* Add `Cldr.Calendar.Preference.preferences_for_territory/1`

* Add `Cldr.Calendar.validate_calendar/1` which returns `{:ok, calendar}` if the argument is a `Cldr.Calendar` calendar module or `{:error, {exception, reason}}` if not.

# Changelog for Cldr Calendars v1.7.1

This is the changelog for Cldr Calendars v1.7.1 released on January 26th, 2020.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Bug Fixes

* Fix doc link in `MyApp.Cldr.Calendar.strftime_options!/2`

# Changelog for Cldr Calendars v1.7.0

This is the changelog for Cldr Calendars v1.7.0 released on January 2nd, 2020.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Remove call to deprecated `Code.ensure_compiled?/1` in Elixir 1.10

# Changelog for Cldr Calendars v1.6.0

This is the changelog for Cldr Calendars v1.6.0 released on December 9th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Adds support for localizing Persian, Coptic and Ethiopic calendar localization. These calendars are published separately but they rely upon localization support from this package.

# Changelog for Cldr Calendars v1.5.1

This is the changelog for Cldr Calendars v1.5.1 released on November 10th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Bug Fixes

* Fix `Cldr.Calendar.next/3` and `Cldr.Calendar.previous/3` for months with week-based calendars. Thanks to @bglusman for the report. Closes #3. Note that the use of the `:coerce` option is recommended in most cases.

# Changelog for Cldr Calendars v1.5.0

This is the changelog for Cldr Calendars v1.5.0 released on November 3rd, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Adds `MyApp.Cldr.Calendar.strftime_options!/2` to return a keyword list of options that can be applied to `NimbleStrftime.format/3`

# Changelog for Cldr Calendars v1.4.0

This is the changelog for Cldr Calendars v1.4.0 released on September 14th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Adjusts `<calendar>.add/3` to `<calendar>.add/5` so that it takes individual date and time elements and not formal structs.  This is consistent with other calendar behaviours.

# Changelog for Cldr Calendars v1.3.0

This is the changelog for Cldr Calendars v1.3.0 released on September 1st, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

Adds `<calendar>.add/3` to add `:quarter` or `:week` to a naive datetime. This adds to the existing support for `:year` and `:month`.

# Changelog for Cldr Calendars v1.2.0

This is the changelog for Cldr Calendars v1.2.0 released on August 31st, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Adds `Cldr.Calendar.Duration` to create a duration struct defining the difference between two dates, times or date_times as a calendar difference in years, months, days, hours, minutes, seconds and microseconds. See `Cldr.Calendar.Duration.new/2` and `Cldr.Calendar.Duration.to_string/1`.

* Changes `sigil_d/2` from a function to a macro so that dates are created at compile time

# Changelog for Cldr Calendars v1.1.0

This is the changelog for Cldr Calendars v1.1.0 released on August 30th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Adds `<calendar>.add/3` to add `:year` or `:month` to a naive datetime.  This function supports the library [calendar_interval](https://hex.pm/packages/calendar_interval) allowing intervals to be used with `ex_cldr_calendars`[https://hex.pm/packages/ex_cldr_calendars]. The mid-term objective is to add `add/3` to the `Calendar` behaviour and thereby also simplify the interface to `CalendarInterval`.

* Changes the output of `to_string/1` to consistently use the full name of the calendar module, not an appreviated name.

# Changelog for Cldr Calendars v1.0.0

This is the changelog for Cldr Calendars v1.0.0 released on June 16th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Breaking changes

* The format produced by inspecting a Date (or DateTime or NaiveDateTime) has changed. The parsing of dates in `sigil_d` (the `~d` sigil) has also changed in order to facilitate roundtrip conversions. Previously a date would inspect as (using the NRF calendar) `~d[2019-W01-1]NRF`. It now inspects as `~d[2019-W01-1 NRF]`.  The same approach is used for all calendars.  See the examples in `Cldr.Calendar.Sigils`. This change is applicable to Elixir 1.10 and later.

* The calendar configuration option `:min_days` has been renamed `:min_days_in_first_week`. The configuration option `:day` has been renamed to `:day_of_week` and the option `:month` has been renamed to `:month_of_year`. An exception will be raised if existing calendars are not updated.

* An exception will be raised if a calendar is configured with an unknown option.

### Enhancements

* Implements `inspect_date/4`, `inspect_datetime/11`, `inspect_naive_datetime/8` and `inspect_time/5` for all `Cldr.Calendar` calendars.  This implementation supports the revised `Inspect` protocol implementation for `Date`, `Time`, `DateTime` and `NaiveDateTime` structs.  The purpose of that change is to allow customer calendars to be inspected. This change is applicable to Elixir 1.10 and later.

* Adds `Cldr.Calendar.week_of_month/1` and `Cldr.Calendar` callback `week_of_month/4` to return the week of a month. The weeks are calculated on the basis of the calendar configuration. As a result, the week of the month, like the week of the year, may be in a different Gregorian year and month compared to the specified date.

* Adds `Cldr.Calendar.weeks_in_year/1` to return the number of weeks in a year.

* Adds a calendar configuration where weeks start on the first day of the year. This configuration is valid only for `:month` based calendars.  The configuration option `day: :first` triggers this behaviour. This configuration can result in the last week of the year being less than 7 days.

* Adds `Cldr.Calendar.inspect/2` that can be used as an `:inspect_fun` option in `Inspect.Opts` for Elixir version 1.9.  It will not be required for Elixir 1.10 and later since [this commit](https://github.com/elixir-lang/elixir/commit/23a68035be96717ca5f8fd20355bdb7bc5ed38f8) introduces `inspect_*` callbacks for `Date`, `Time`, `DateTime` and `NaiveDateTime`. An `:inspect_fun` can be configured in `IEx` by:

```elixir
iex> IEx.configure(inspect: [inspect_fun: &Cldr.Calendar.inspect/2])
:ok
```

### Bug Fixes

* Ensure that `Cldr.Calendar` callbacks return a `Calendar.ISO` calendar if called with one (either as part of a date or as a separate argument).

* Ensure the return calendar types of a an Interval are `Calendar.ISO` is the date provided is `Calendar.ISO`

* Fix `Cldr.Calendar.plus/4` for `:months` when the month wraps into the previous year(s)

* Fix `sigil_d` to correctly parse ISO Week dates that have only a single digit day

# Changelog for Cldr Calendars v0.9.0

This is the changelog for Cldr Calendars v0.9.0 released on June 9th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Breaking changes

* Depends on Elixir 1.8 and above since it requires recent `Calendar` functionality.

# Changelog for Cldr Calendars v0.8.0

This is the changelog for Cldr v0.8.0 released on June 8th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Adds option `:type` to `Cldr.Calendar.localize/3`. This determines the format type to be localized. The valid types are `:format` (the default) or `:stand_alone`.

* Add `Cldr.Calendar.day_periods/2` to support localization of the day periods of a time

* Add `Cldr.Calendar.default_calendar/0`. Returns `Cldr.Calendar.Gregorian`

* Add `Cldr.Calendar.default_cldr_calendar/0`. Returns `:gregorian`

# Changelog for Cldr Calendars v0.7.0

This is the changelog for Cldr Calendars v0.7.0 released on June 1st, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Breaking Changes

* Moved `year/1`, `quarter/1`, `month/1`, `week/1` and `day/1` to a new module `Cldr.Calendar.Interval`

### Enhancements

* Adds `Cldr.Calendar.Interval.compare/2` to compare two intervals (date ranges) using [Allen's Interval Algebra](https://en.wikipedia.org/wiki/Allen%27s_interval_algebra) taxonomy.

* Defaults the calendar to `Cldr.Calendar.Gregorian` for `Cldr.Calendar.Interval.year/2`, `Cldr.Calendar.Interval.quarter/3`, `Cldr.Calendar.Interval.month/3`, `Cldr.Calendar.Interval.week/3` and `Cldr.Calendar.Interval.day/3`

# Changelog for Cldr Calendars v0.6.0

This is the changelog for Cldr Calendars v0.6.0 released on April 28th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Remove the need for [nimble_csv](https://hex.pm/nimble_csv) as a dependency

# Changelog for Cldr Calendars v0.5.0

This is the changelog for Cldr Calendars v0.5.0 released on April 21th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Breaking changes

* `Cldr.Calendar.localize/3` for `:days_of_week` now returns a list of 2-tuples that are of the format `{day_of_week, day_name}`.

### Enhancements

* Add `Cldr.Calendar.localize/6` which localises numbers as part of a date without parameter checking.  This is considered a private implementation for now.

# Changelog for Cldr Calendars v0.4.1

This is the changelog for Cldr Calendars v0.4.1 released on April 19th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Bug Fixes

* Fix calculation of `days_in_month` for the last month in long year of a week-based calendar

# Changelog for Cldr Calendars v0.4.0

This is the changelog for Cldr Calendars v0.4.0 released on April 19th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Adds `Cldr.Calendar.interval_stream/3` which returns a stream function that when enumerated generates a list of dates with a specified precision of either `:years`, `:quarters`, `:months`, `:weeks` or `:days`. This function has the same arguments and generates the same results as `Cldr.Calendar.interval/3` except it generates the results lazily.

* Adds `:days_of_week` option to `Cldr.Calendar.localize/3` which returns a list of the localized names of the days of the week in calendar order.

* Adds `calendar_base/0` to identify whether the calendar is week or month based.

### Bug Fixes

* Fix `Cldr.Calendar.day_of_week/1` for week-based calendars

# Changelog for Cldr Calendars v0.3.0

This is the changelog for Cldr Calendars v0.3.0 released on April 16th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Adds `Cldr.Calendar.interval/3` which generates an enumerable list of dates with a specified precision of either `:years`, `:quarters`, `:months`, `:weeks` or `:days`.

### Examples:
```
iex> import Cldr.Calendar.Sigils
Cldr.Calendar.Sigils

iex> d = ~d[2019-01-31]
%Date{calendar: Cldr.Calendar.Gregorian, day: 31, month: 1, year: 2019}

iex> d2 = ~d[2019-05-31]
%Date{calendar: Cldr.Calendar.Gregorian, day: 31, month: 5, year: 2019}

iex> Cldr.Calendar.interval d, 3, :months
[
  %Date{calendar: Cldr.Calendar.Gregorian, day: 28, month: 2, year: 2019},
  %Date{calendar: Cldr.Calendar.Gregorian, day: 31, month: 3, year: 2019},
  %Date{calendar: Cldr.Calendar.Gregorian, day: 30, month: 4, year: 2019}
]

iex> Cldr.Calendar.interval d, d2, :months
[
  %Date{calendar: Cldr.Calendar.Gregorian, day: 31, month: 1, year: 2019},
  %Date{calendar: Cldr.Calendar.Gregorian, day: 28, month: 2, year: 2019},
  %Date{calendar: Cldr.Calendar.Gregorian, day: 31, month: 3, year: 2019},
  %Date{calendar: Cldr.Calendar.Gregorian, day: 30, month: 4, year: 2019},
  %Date{calendar: Cldr.Calendar.Gregorian, day: 31, month: 5, year: 2019}
]
```
# Changelog for Cldr Calendars v0.2.0

This is the changelog for Cldr Calendars v0.2.0 released on April 14th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Breaking Changes

* All calendars now return `{year, month, day}` tuples from `date_from_iso_days/1`. Previously in some cases they returned a `Date.t`

* `first_day_of_year/1` and `last_day_of_year/1`, `first_gregorian_day_of_year/1` and `last_gregorian_day_of_year/1` now all return a `Date.t` or an error tuple.  Previously the returned result types were inconsistent.

* Remove `first_gregorian_day_of_year/1` and `last_gregorian_day_of_year/1` from `Cldr.Calendar` callbacks.

### Enhancements

* Adds `Cldr.Calendar.Julian` implementing the Julian calendar. This calendar does not implement `week/2`, `week_of_year/3` or `iso_week_of_year/3`.

### Bug Fixes

* Fixes calculating negative offsets for months in a week-based calendar.  Thanks to @bglusman. Closes #2.

# Changelog for Cldr Calendars v0.1.0

This is the changelog for Cldr Calendars v0.1.0 released on April 5th, 2019.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-cldr/cldr_calendars/tags)

### Enhancements

* Initial release.  See the README for a description of this project.