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lib/format.ex
defmodule Momento.Format do
@moduledoc """
This module holds all the `format/2` method.
"""
@doc """
Provide a `DateTime` struct and token string to get back a formatted date/datetime string.
## Examples
iex> Momento.date |> Momento.format("YYYY-MM-DD")
"2016-07-01"
...> Momento.date |> Momento.format("M-D-YY")
"7-1-16"
"""
@tokens ~r/YYYY|YY?|Mo|MM?M?M?|Do|DD?D?D?|HH?|hh?|mm?|ss?|X|x/
@spec format(DateTime.t, String.t) :: String.t
# An implementation of the Moment.js formats listed here: http://momentjs.com/docs/#/displaying/format/
# TODO: Add support for escaping characters within square brackets []
def format(%DateTime{} = datetime, format_string)
when is_bitstring(format_string)
do
# Split the format_string into pieces by tokens
Regex.split(@tokens, format_string, include_captures: true, trim: true)
# Convert each token
|> Enum.map(fn token ->
case token do
# 1970 1971 ... 2029 2030
"YYYY" -> datetime.year |> Integer.to_string
# 70 71 ... 29 30
"YY" -> rem(datetime.year, 100) |> Integer.to_string
# TODO: 1970 1971 ... 9999 +10000 +10001
# "Y" -> datetime.year |> Integer.to_string)
# January February ... November December
"MMMM" -> datetime.month |> get_month_name
# Jan Feb ... Nov Dec
"MMM" -> datetime.month |> get_month_name(:MMM)
# 01 02 ... 11 12
"MM" -> datetime.month |> Integer.to_string |> String.rjust(2, ?0)
# 1 2 ... 11 12
"M" -> datetime.month |> Integer.to_string
# 1st 2nd ... 11th 12th
"Mo" -> datetime.month |> get_ordinal_form
# TODO: 001 002 ... 364 365
# "DDDD" -> datetime.day |> Integer.to_string
# TODO: 1st 2nd ... 364th 365th
# "DDDo" -> datetime.day |> Integer.to_string
# TODO: 1 2 ... 364 365
# "DDD" -> datetime.day |> Integer.to_string
# 01 02 ... 30 31
"DD" -> datetime.day |> Integer.to_string |> String.rjust(2, ?0)
# 1st 2nd ... 30th 31st
"Do" -> datetime.day |> get_ordinal_form
# 1 2 ... 30 31
"D" -> datetime.day |> Integer.to_string
# TODO: Sunday Monday ... Friday Saturday
# "dddd" -> datetime.day |> Integer.to_string
# TODO: Sun Mon ... Fri Sat
# "ddd" -> datetime.day |> Integer.to_string
# TODO: Su Mo ... Fr Sa
# "dd" -> datetime.day |> Integer.to_string
# TODO: 0th 1st ... 5th 6th
# "do" -> datetime.day |> Integer.to_string
# TODO: 0 1 ... 5 6
# "d" -> datetime.day |> Integer.to_string
# 00 01 ... 22 23
"HH" -> datetime.hour |> Integer.to_string |> String.rjust(2, ?0)
# 0 1 ... 22 23
"H" -> datetime.hour |> Integer.to_string
# 01 02 ... 11 12
"hh" -> datetime.hour |> twelve_hour_format(:hh)
# 1 2 ... 11 12
"h" -> datetime.hour |> twelve_hour_format
# TODO: 01 02 ... 23 24
# "kk" -> datetime.hour |> Integer.to_string
# TODO: 1 2 ... 23 24
# "k" -> datetime.hour |> Integer.to_string
# 00 01 ... 58 59
"mm" -> datetime.minute |> Integer.to_string |> String.rjust(2, ?0)
# 0 1 ... 58 59
"m" -> datetime.minute |> Integer.to_string
# 00 01 ... 58 59
"ss" -> datetime.second |> Integer.to_string |> String.rjust(2, ?0)
# 0 1 ... 58 59
"s" -> datetime.second |> Integer.to_string
# TODO: 000[0..] 001[0..] ... 998[0..] 999[0..]
# ~r/S{4,9}/ -> datetime.second |> Integer.to_string
# TODO: 000 001 ... 998 999
# "SSS" -> datetime.second |> Integer.to_string
# TODO: 00 01 ... 98 99
# "SS" -> datetime.second |> Integer.to_string
# TODO: 0 1 ... 8 9
# "S" -> datetime.second |> Integer.to_string
# TODO: -0700 -0600 ... +0600 +0700
# "ZZ" -> datetime.time_zone
# TODO: -07:00 -06:00 ... +06:00 +07:00
# "Z" -> datetime.time_zone
# TODO: AM PM
# "A" -> datetime.hour |> Integer.to_string
# TODO: am pm
# "a" -> datetime.hour |> Integer.to_string
# TODO: 1 2 3 4
# "Q" -> datetime.month |> Integer.to_string
# TODO: 1st 2nd 3rd 4th
# "Qo" -> datetime.month |> Integer.to_string
# TODO: 1 2 ... 6 7
# "E" -> datetime
# TODO: 0 1 ... 5 6
# "e" -> datetime
# TODO: 01 02 ... 52 53
# "WW" -> datetime
# TODO: 1st 2nd ... 52nd 53rd
# "Wo" -> datetime
# TODO: 1 2 ... 52 53
# "W" -> datetime
# TODO: 01 02 ... 52 53
# "ww" -> datetime
# TODO: 1st 2nd ... 52nd 53rd
# "wo" -> datetime
# TODO: 1 2 ... 52 53
# "w" -> datetime
# TODO: 1970 1971 ... 2029 2030
# "GGGG" -> datetime
# TODO: 70 71 ... 29 30
# "GG" -> datetime
# TODO: 1970 1971 ... 2029 2030
# "gggg" -> datetime
# TODO: 70 71 ... 29 30
# "gg" -> datetime
# TODO: Thursday, September 4 1986 8:30 PM
# "LLLL" -> datetime
# TODO: September 4 1986 8:30 PM
# "LLL" -> datetime
# TODO: September 4 1986
# "LL" -> datetime
# TODO: 8:30:25 PM
# "LTS" -> datetime
# TODO: 8:30 PM
# "LT" -> datetime
# TODO: 09/04/1986
# "L" -> datetime
# TODO: Thu, Sep 4 1986 8:30 PM
# "llll" -> datetime
# TODO: Sep 4 1986 8:30 PM
# "lll" -> datetime
# TODO: Sep 4 1986
# "ll" -> datetime
# TODO: 9/4/1986
# "l" -> datetime
# 1360013296
"X" -> datetime |> DateTime.to_unix |> Integer.to_string
# 1360013296123
"x" -> datetime |> DateTime.to_unix(:milliseconds) |> Integer.to_string
_ -> token
end
end)
# Recombine the pieces
|> Enum.join
end
defp get_month_name(month_number, token \\ :MMMM) do
month_name = elem({"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"}, month_number-1)
case token do
:MMM -> String.slice(month_name, 0..2)
_ -> month_name
end
end
defp get_ordinal_form(number) do
number_rem_hundred = rem(number, 100)
ordinal_form =
if number_rem_hundred == 11 || number_rem_hundred == 12 || number_rem_hundred == 13 do
"th"
else
number_rem_ten = rem(number, 10)
cond do
number_rem_ten == 1 -> "st"
number_rem_ten == 2 -> "nd"
number_rem_ten == 3 -> "rd"
true -> "th"
end
end
Integer.to_string(number) <> ordinal_form
end
defp twelve_hour_format(hour, token \\ :h) do
adjusted_hour =
cond do
hour >= 13 -> hour - 12
hour == 0 -> 12
true -> hour
end
adjusted_hour = Integer.to_string(adjusted_hour)
case token do
:hh -> adjusted_hour |> String.pad_leading(2, "0")
_ -> adjusted_hour
end
end
end