The new calendar types in Elixir 1.3

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Calendar types in Elixir 1.3 ElixirConf 2016

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Lau Taarnskov Software developer Open source contributor. Creator of Calendar for Elixir and tzdata Blog: creativedeletion.com Twitter: @laut Github: lau

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Lau Taarnskov - twitter: @LauT What is a type?

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Lau Taarnskov - twitter: @LauT Why have types?

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Lau Taarnskov - twitter: @LauT iex(1)> 5/2 2.5

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Lau Taarnskov - twitter: @LauT iex(1)> 5/2 2.5 iex(2)> 5/"Orlando" ** (ArithmeticError) bad argument in arithmetic expression :erlang./(5, "Orlando")

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Lau Taarnskov - twitter: @LauT We want errors instead of non-sensical results

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Lau Taarnskov - twitter: @LauT Explicit data

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Lau Taarnskov - twitter: @LauT

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Lau Taarnskov - twitter: @LauT Mars Climate Orbiter Mission cost: $327.6 million Mission failure after a 286 day journey to Mars

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Lau Taarnskov - twitter: @LauT Newton-seconds? Oh, we used pound seconds.

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Lau Taarnskov - twitter: @LauT 5, 6, 3, 9, 4, 5…

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Lau Taarnskov - twitter: @LauT {5, :lbs_s}, {6, :lbs_s}, {3, :lbs_s}, {9, :lbs_s}, {4, :lbs_s}, {5, :lbs_s}…

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Lau Taarnskov - twitter: @LauT %ThrusterData{amount: 5, unit: :lbs_s}, %ThrusterData{amount: 6, unit: :lbs_s}, %ThrusterData{amount: 3, unit: :lbs_s},

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Lau Taarnskov - twitter: @LauT def process_thruster_data(%{amount: amount, unit: :n_s}) do # ... end ** (FunctionClauseError) no function clause matching in ThrustProcessor.process_thruster_data/1 thruster.ex:12: ThrustProcessor.process_thruster_data(%ThrusterData{amou nt: 3, unit: :lbs_s}) thruster.ex:17: (ﬁle) (elixir) lib/code.ex:363: Code.require_ﬁle/2

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Lau Taarnskov - twitter: @LauT Different units of time and date

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Lau Taarnskov - twitter: @LauT 2016 2016 September 2016 September 2nd 2016 September 2nd at 14:01:03 2016-09-02 at 14:01:03 in New York 14:01 14:01:03 14:01:03.9472 ….

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Lau Taarnskov - twitter: @LauT One type to rule them all?

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Lau Taarnskov - twitter: @LauT 2016-09-02 2016-09-02 00:00:00.000 UTC

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Lau Taarnskov - twitter: @LauT 06:10 2001-01-01 06:10:00.000 UTC

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Lau Taarnskov - twitter: @LauT 2001-01-01 00:00:00.000 2001-01-01 06:10:00.000 UTC

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Lau Taarnskov - twitter: @LauT 6:10 What year is that in? 2001 (!!!!!!!)

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Lau Taarnskov - twitter: @LauT 2016-09-02 At what hour and minute? 00:00 (!!!)

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Lau Taarnskov - twitter: @LauT Year Year with month Year, month, day of month Hour Hour and minute Hour and minute and second …

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Lau Taarnskov - twitter: @LauT The structs in the Calendar library

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Lau Taarnskov - twitter: @LauT Types in Calendar in 2014 Calendar.Date Calendar.Time Calendar.NaiveDateTime Calendar.DateTime

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Lau Taarnskov - twitter: @LauT Date: year, month, day

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Lau Taarnskov - twitter: @LauT Time: hour, minute, second, microsecond

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Lau Taarnskov - twitter: @LauT NaiveDateTime: year, month, day, hour, minute, second, microsecond

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Lau Taarnskov - twitter: @LauT DateTime: year, month, day, hour, minute, second, microsecond, time zone, UTC offset, standard offset, zone abbreviation

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Lau Taarnskov - twitter: @LauT Local vs Naive

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Lau Taarnskov - twitter: @LauT JAVA 8 Class LocalDate A date without a time-zone in the ISO-8601 calendar system, such as 2007-12-03.

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Lau Taarnskov - twitter: @LauT local |ˈlōk(ə)l| adjective belonging or relating to a particular area or neighborhood, typically exclusively so: researching local history | the local post oﬃce.

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Lau Taarnskov - twitter: @LauT

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Lau Taarnskov - twitter: @LauT ~N[1970-01-01 00:00:00] |> DateTime.to_unix ** (FunctionClauseError) no function clause matching in DateTime.to_unix/2 (elixir) lib/calendar.ex:1078: DateTime.to_unix(~N[1970-01-01 00:00:00], :seconds)

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Lau Taarnskov - twitter: @LauT The structs built into Elixir 1.3

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Lau Taarnskov - twitter: @LauT Types in Calendar in 2014 Types in Elixir 1.3 in 2016 Calendar.Date Date Calendar.Time Time Calendar.NaiveDateTime NaiveDateTime Calendar.DateTime DateTime

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Lau Taarnskov - twitter: @LauT Sigils ~D[2016-09-02] ~T[14:15:00] ~N[2016-09-02 14:15:00]

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Lau Taarnskov - twitter: @LauT %DateTime{calendar: Calendar.ISO, day: 1, hour: 0, microsecond: {0, 0}, …

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Lau Taarnskov - twitter: @LauT %DateTime{calendar: Calendar.ISO, day: 1, hour: 0, microsecond: {0, 0}, …

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Lau Taarnskov - twitter: @LauT "2016-09-02 14:15:00.1234” |> NaiveDateTime.from_iso8601! ~N[2016-09-02 14:15:00.1234] "2016-09-02 14:15:00.1” |> NaiveDateTime.from_iso8601! ~N[2016-09-02 14:15:00.1] Signiﬁcant fractional seconds

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Lau Taarnskov - twitter: @LauT "2016-09-02 14:15:00.1234” |> NaiveDateTime.from_iso8601! |> Map.get(:microsecond) {123400, 4} "2016-09-02 14:15:00.10” |> NaiveDateTime.from_iso8601! |> Map.get(:microsecond) {100000, 2} "2016-09-02 14:15:00” |> NaiveDateTime.from_iso8601! |> Map.get(:microsecond) {0, 0} Signiﬁcant fractional seconds

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Lau Taarnskov - twitter: @LauT Time zones and more functionality with the Calendar library

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Lau Taarnskov - twitter: @LauT The Calendar library

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Lau Taarnskov - twitter: @LauT ~N[1970-01-01 00:00:00] |> Calendar.NaiveDateTime.to_date_time_utc |> DateTime.to_unix 0

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Lau Taarnskov - twitter: @LauT DateTime.from_unix!(1472836167) %DateTime{calendar: Calendar.ISO, day: 2, hour: 17, microsecond: {0, 0}, minute: 9, month: 9, second: 27, std_offset: 0, time_zone: "Etc/UTC", utc_offset: 0, year: 2016, zone_abbr: "UTC"}

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Lau Taarnskov - twitter: @LauT DateTime.from_unix!(1472836167) |> Calendar.DateTime.shift_zone!("America/New_York") %DateTime{calendar: Calendar.ISO, day: 2, hour: 13, microsecond: {0, 0}, minute: 9, month: 9, second: 27, std_offset: 3600, time_zone: "America/New_York", utc_offset: -18000, year: 2016, zone_abbr: "EDT"}

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Lau Taarnskov - twitter: @LauT DateTime.from_unix!(1472836167) |> Calendar.DateTime.shift_zone(“America/New_York”) |> DateTime.to_iso8601 "2016-09-02T13:09:27-04:00"

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Lau Taarnskov - twitter: @LauT DateTime.from_unix(1472836167) |> Calendar.DateTime.shift_zone!(“America/New_York”) |> Calendar.Strftime.strftime!("%Y %B %d, %H:%M:%S %Z") "2016 September 02, 13:09:27 EDT"

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Lau Taarnskov - twitter: @LauT ~D[2016-09-02] |> Calendar.Date.friday? true

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Lau Taarnskov - twitter: @LauT ~D[2016-09-02] |> Calendar.Date.before? (~D[2016-09-03]) true

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Lau Taarnskov - twitter: @LauT ~D[2016-09-02] |>Calendar.Date.next_day! ~D[2016-09-03]

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Lau Taarnskov - twitter: @LauT Calendar.Date.today(“Amer ica/New_York") |> Calendar.Date.next_day! ~D[2016-09-03]

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Lau Taarnskov - twitter: @LauT ~D[2016-09-02] |> Calendar.Date.add!(7) |> Date.to_iso8601 "2016-09-09"