Merge branch 'master' of https://github.com/Louis-Aime/Milesian-calen…

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README.md

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 # Milesian-calendar-VBA
 Excel VBA functions for Milesian calendar computations
+
+Copyright (c) Miletus, Louis-Aimé de Fouquières, 2017
+
+MIT licence applies
+
+MAC OS users: check date conversion starting from 1904.
+
+## Installation
+1. Create a new Excel file, save as "Excel file with macros".
+1. If you don't see the "developer" menu, get access to this menu through Excel Options.
+1. In "developer" menu, choose "Visual Basic" (lefmost).
+1. A Visual Basic sheet opens. In "File" menu of this sheet, choose "Import file".
+1. Import the suitable .bas files of the release. You may import one or several.
+1. After importing, you see new "modules", one for each .bas file. You can see the source code and comments.
+1. In "File" menu, hit "Close and back to Excel".
+1. In Excel file, you can call the fucntions of the modules you selected.
+
+## Using the functions
+* Hit "insert function" near the input bar.
+* Choose "custom" - you can see the functions.
+* If you choose one function, the parameter list appear (sorry, no help in this version).
+* Functions are sensitive to "1904 Calendar" (by default on MacOS)
+
+## MilesianCalendar
+Compute a system date with Milesian date elements, or retrieve Milesian date elements from a system date.
+### MILESIAN_IS_LONG_YEAR (Y)
+Boolean, whether the year is long (366 days) or not. 
+* Y, the year in question.
+
+A long Milesian year is just before a leap year, e.g. 2015 is a long year because 2016 is a leap year. 
+With the Milesian calendar, a proposed rule is this:
+years -4001, -801, 2399, 5599 etc. are *not* long. Elsewise the Gregorian rules are applied, 
+e.g. 1899 is *not* long whereas 1999 is.
+Remember that by mistake, dates 1/1/1900 to 29/2/1900 are wrong under Microsoft Windows.
+
+### MILESIAN_YEAR_BASE (Y) 
+Date of the day before the 1 1m of year Y, i.e. the "doomsday".
+
+### Other functions of this module 
+They work like the standard date-time functions of Excel. 
+Under Microsoft (1900-calendar), negative results are handled. Excel does not display those date.
+The minimum negative value is around (julian) January of year 100. 
+Under MacOS, no date before 1 Jan 1904 can be handled.
+
+* MILESIAN_YEAR, MILESIAN_MONTH, MILESIAN_DAY: the Milesian date elements of an Excel date-time stamp.
+* MILESIAN_DISPLAY (D) : a string that expresses a date in Milesian.
+* MILESIAN_MONTH_END : works like MONTH.END.
+* MILESIAN_MONTH_SHIFT : works like MONTH.SHIFT.
+
+## Milesian moon
+Next or last mean moon. Error is +/- 6 hours for +/- 3000 years from year 2000.
+### LastMoonPhase (FromDate, Moonphase)
+Date of last new moon, or of other specified moon phase. Result is in Terrestrial Time.
+* FromDate: Base Excel date;
+* MoonPhase (0 by default): 0 for new moon, 1 for 1st quarter, 2 for full moon, 3 for last quarter.
+### NextMoonPhase (FromDate, Moonphase)
+Similar, but computes next moon phase.
+
+
+
+