QDates

The QDates package provides Japanese "Kyūreki (旧暦)" calendrical calculations into Julia.
"Kyūreki (旧暦)" is one of the Lunisolar Calendar that has been once used in Japan.

Installation

To install the release version, simply run on the Julia Pkg REPL-mode:

pkg> add QDates

To install the latest development version, run the following command instead:

pkg> add QDates#master

Then you can run the built-in unit tests with

pkg> test QDates

to verify that everything is functioning properly on your machine.

Usage

QDates has APIs almost compatible with the standard Dates package.

using QDates

### construct Kyūreki Date
qdt = QDate(2017, 5, 1)
# => 旧2017年05月01日

### get year/month/day values
using Dates
Dates.yearmonthday(qdt)
# => (2017,5,1)

### check leapmonth or not
QDates.isleapmonth(qdt)
# => false

### arithmetic
qdt1 = qdt + Dates.Month(1)
# => 旧2017年閏05月01日

### check leapmonth or not
QDates.isleapmonth(qdt1)
# => true

### get year/month/isleapmonth/day values
QDates.yearmonthleapday(qdt1)
# => (2017,5,true,1)

### comparison (with constructing leapmonth-date)
qdt1 == QDate(2017, 5, true, 1)
# => true

### conversion to Gregorian Date
dt = Date(qdt)
# => 2017-05-26

### conversion from Gregorian Date
qdt0 = QDate(dt)
# => 旧2017年05月01日

### get today
qtoday = QDates.today()
# => 旧2017年04月10日
qtoday == QDate(Dates.today())
# => true

### six-day week system
[QDates.dayname(d) for d=qdt:QDate(2017,5,7)]
# => 7-element Array{String,1}:
#     "大安"
#     "赤口"
#     "先勝"
#     "友引"
#     "先負"
#     "仏滅"
#     "大安"

[d for d=qdt:qdt1 if QDates.is大安(d)]
# => 6-element Array{QDates.QDate,1}:
#     旧2017年05月01日
#     旧2017年05月07日
#     旧2017年05月13日
#     旧2017年05月19日
#     旧2017年05月25日
#     旧2017年閏05月01日

### month names (old-fashioned)
[QDates.monthname(m) for m=QDate(2017,1):Dates.Month(1):QDate(2017,12)]
# => 13-element Array{String,1}:
#     "睦月"
#     "如月"
#     "弥生"
#     "卯月"
#     "皐月"
#     "閏皐月" # <- means leapmonth("閏月") of "皐月"
#     "水無月"
#     "文月"
#     "葉月"
#     "長月"
#     "神無月"
#     "霜月"
#     "師走"

### The number of days in a month (29 or 30, not constant).
[QDates.daysinmonth(m) for m=QDate(2017,1):Dates.Month(1):QDate(2017,12)]
# => 13-element Array{Int64,1}:
#     29 # 1月
#     30 # 2月
#     29 # 3月
#     30 # 4月
#     29 # 5月
#     29 # 閏5月
#     30 # 6月
#     29 # 7月
#     30 # 8月
#     29 # 9月
#     30 # 10月
#     30 # 11月
#     30 # 12月

### leapyear or not (⇔ including leapmonth or not, not constant)
[QDates.isleapyear(y) for y=QDate(2011):Dates.Year(1):QDate(2020)]
# => 10-element Array{Bool,1}:
#     false # 2011
#      true # 2012
#     false # 2013
#      true # 2014
#     false # 2015
#     false # 2016
#      true # 2017
#     false # 2018
#     false # 2019
#      true # 2020

Requirements

• Julia (VERSION ≥ v"1.0", ready for v"1.1")
  • QDates v0.0.2 is available for Julia of VERSION < v"0.6"
  • QDates v0.1.0 is available for Julia of VERSION < v"1.0"
• Dates module

Limitations

• Year range is 445-2200. QDate(2201) throws ArgumentError.

Credits

QDates.jl is created by @antimon2 (Shunsuke GOTOH).