Re: Help with Project

[email protected] (Troy Davis) Fri, 16 May 2008 17:06:00 -0400

Newsgroups	perl.datetime
Message-ID	<[email protected]>

Hi Cyrus,

I don't know if this would interest you or not, but I've ported a C  
program to a perl script that computes the date according to the  
Tranquility calendar (centered on the first moon landing). I've been  
wanting to port this to DateTime, but it's got some unique features  
like 13 months and 1 or 2 null days per year. The Hebrew calendar  
module for DateTime also has 13 months, and I was looking at that as a  
possible model to build upon, but it's messy. I can't recall if they  
have any calendars that have null days, however.

Anyway, here's the script. If nothing else, I hope you find it  
entertaining.

Cheers,
Troy

On May 15, 2008, at 12:31 PM, Cyrus Noble wrote:

> I am new to the DateTime project, and I am interested in helping  
> with a
> calender.
>
> I can't easily locate a TODO list; however, are any of the calenders
> open for work?  How about Hindu or Islamic?
>
>

tranquility.pl (text/x-perl-script, 2.7 KB)

#!/usr/bin/perl 
# This product includes software developed by Scott M Harrison (mailto://[email protected]).
# Ported to perl by Troy Davis (mailto://[email protected])

use strict;
use Switch;
use Time::Local;
use Data::Dumper;

print tranquility_date() . "\n";
exit();


sub tranquility_date() {
	my ($dayOfYear, $yearOfCommonEra) = @_;
	my $show_date = 0;
	my ($second,$minute,$hour,$dayOfMonth,$month,$dayOfWeek);
	if (($dayOfYear =! /^\d+/) && ($dayOfYear > 0)  && ($dayOfYear < 367) && ($yearOfCommonEra =~ /^(-{1})*\d+$/)) {
		# Values passed in look legit
	} else {
		# Assume now in UTC time zone
		$ENV{TZ} = ':/usr/share/zoneinfo/UTC'; 
		($second,$minute,$hour,$dayOfMonth,$month,$yearOfCommonEra,$dayOfWeek,$dayOfYear) = localtime();
		$dayOfYear++;
		$yearOfCommonEra += 1900;
		$show_date = 1;
	}

	my @daysOfWeek = ( "Thursday", "Friday", "Saturday", "Sunday", "Monday", "Tuesday", "Wednesday" );
	my @months = ( "Archimedes", "Brahe", "Copernicus", "Darwin", "Einstein", "Faraday", "Galileo", "Hippocrates", "Imhotep", "Jung", "Kepler", "Lavoisier", "Mendel" );
	my $daysInNonLeapYear = 365;
	my $daysInTranquilityMonth = 28;
	my $aldrinDay = 60;
	my $armstrongDay = 201;
	my $yearOfTranquility = 1969;
	my $isLeapYear = ((($yearOfCommonEra % 4) == 0) && (($yearOfCommonEra % 400) != 100) && (($yearOfCommonEra % 400) != 200) && (($yearOfCommonEra % 400) != 300));
	my $tranquilityDayOfYear = 0;
	my $specialDay = 0;
	my $day = 0;
	my $month = 1;
	my $year;
	my $afterArmstrongDay = $dayOfYear > $armstrongDay;

	if ($isLeapYear) {
		if ($dayOfYear > $aldrinDay) {
			$dayOfYear--;
		}
		elsif ($dayOfYear == $aldrinDay) {
			$specialDay = 1;
		}
	}
	if ($dayOfYear == $armstrongDay) {
		$specialDay = 2;
	}

	$tranquilityDayOfYear = $dayOfYear - $armstrongDay + ($afterArmstrongDay ? 0 : $daysInNonLeapYear);
	
	if ($specialDay == 0) {
		$month = sprintf("%d", ($tranquilityDayOfYear - 1) / $daysInTranquilityMonth);
		$day = $tranquilityDayOfYear - $month * $daysInTranquilityMonth;
	}
	elsif (($yearOfCommonEra == $yearOfTranquility) && ($specialDay == 2)) {
		$specialDay = 3;
	}

	$year = $yearOfCommonEra - $yearOfTranquility + ($afterArmstrongDay ? 1 : 0);
	if ($year <= 0) { $year--; }
	
	my $out = '';
	
	switch ($specialDay) {
		case 0 { $out .= $daysOfWeek[$day % 7] . ', ' . $months[$month] . " " . $day . ","; next }
		case 1 { $out .= "Aldrin Day $year"; next }
		case 2 { $out .= "Armstrong Day $year"; next }
		case 3 { $out .= "Moon Landing Day"; }
		}
	if (3 != $specialDay) {
		$out .= sprintf(" %d", abs($year));
		if ($year < 0) { $out .= " BT"; }
	}
	if ($show_date) {
		$out .= " " . sprintf("%02d", $hour) . ':' . sprintf("%02d", $minute) . ':' . sprintf("%02d", $second) . " UTC";
	}
	return $out;
}