summaryrefslogtreecommitdiff
path: root/Master/texmf-dist/tex/generic/genmisc/dayofweek.tex
diff options
context:
space:
mode:
Diffstat (limited to 'Master/texmf-dist/tex/generic/genmisc/dayofweek.tex')
-rw-r--r--Master/texmf-dist/tex/generic/genmisc/dayofweek.tex149
1 files changed, 149 insertions, 0 deletions
diff --git a/Master/texmf-dist/tex/generic/genmisc/dayofweek.tex b/Master/texmf-dist/tex/generic/genmisc/dayofweek.tex
new file mode 100644
index 00000000000..4ce46ac2434
--- /dev/null
+++ b/Master/texmf-dist/tex/generic/genmisc/dayofweek.tex
@@ -0,0 +1,149 @@
+%
+% \DayOfWeek expands to the day of the week ("Sunday", etc.)
+% \PhaseOfMoon expands to the phase of the moon
+%
+% Written by Martin Minow of DEC (minow%bolt.dec@decwrl.dec.com).
+%
+\def\DayOfWeek{%
+%
+% Calculate day of the week, return "Sunday", etc.
+%
+ \newcount\dow % Gets day of the week
+ \newcount\leap % Leap year fingaler
+ \newcount\x % Temp register
+ \newcount\y % Another temp register
+% leap = year + (month - 14)/12;
+ \leap=\month \advance\leap by -14 \divide\leap by 12
+ \advance\leap by \year
+% dow = (13 * (month + 10 - (month + 10)/13*12) - 1)/5
+ \dow=\month \advance\dow by 10
+ \y=\dow \divide\y by 13 \multiply\y by 12
+ \advance\dow by -\y \multiply\dow by 13 \advance\dow by -1 \divide\dow by 5
+% dow += day + 77 + 5 * (leap % 100)/4
+ \advance\dow by \day \advance\dow by 77
+ \x=\leap \y=\x \divide\y by 100 \multiply\y by 100 \advance\x by -\y
+ \multiply\x by 5 \divide\x by 4 \advance\dow by \x
+% dow += leap / 400
+ \x=\leap \divide\x by 400 \advance\dow by \x
+% dow -= leap / 100 * 2;
+% dow = (dow % 7)
+ \x=\leap \divide\x by 100 \multiply\x by 2 \advance\dow by -\x
+ \x=\dow \divide\x by 7 \multiply\x by 7 \advance\dow by -\x
+ \ifcase\dow Sunday\or Monday\or Tuesday\or Wednesday\or
+ Thursday\or Friday\or Saturday\fi
+}
+%%
+%%
+%%
+\def\PhaseOfMoon{% Calculate the phase of the (civil) moon.
+%
+% The routine calculates the year's epact (the age of the moon on Jan 1.),
+% adds this to the number of days in the year, and calculates the phase
+% of the moon for this date. It returns the phase as a string, e.g.,
+% "new", "full", etc.
+%
+% In the algorithm:
+%
+% diy Is the day of the year - 1 (i.e., Jan 1 is day 0).
+%
+% golden Is the number of the year in the Mentonic cycle, used to
+% determine the position of the calender moon.
+%
+% epact Is the age of the calender moon (in days) at the beginning
+% of the year. To calculate epact, two century-based
+% corrections are applied:
+% Gregorian: (3 * cent)/4 - 12
+% is the number of years such as 1700, 1800 when
+% leap year was not held.
+% Clavian: (((8 * cent) + 5) / 25) - 5
+% is a correction to the Mentonic cycle of about
+% 8 days every 2500 years. Note that this will
+% overflow 16 bits in the year 409600. Beware.
+%
+% The algorithm is accurate for the Gregorian calender only.
+%
+% The magic numbers used in the phase calculation are as follows:
+% 29.5 The moon's period in days.
+% 177 29.5 scaled by 6
+% 22 (29.5 / 8) scaled by 6 (this gets the phase)
+% 11 ((29.5 / 8) / 2) scaled by 6
+%
+% Theoretically, this should yield a number in the range 0 .. 7. However,
+% two days per year, things don't work out too well.
+%
+% Epact is calculated by the algorithm given in Knuth vol. 1 (calculation
+% of Easter). See also the article on Calenders in the Encyclopaedia
+% Britannica and Knuth's algorithm in CACM April 1962, page 209.
+%
+ \newcount\cent % Century number (1979 == 20)
+ \newcount\epact % Age of the moon on Jan. 1
+ \newcount\diy % Day in the year
+ \newcount\golden % Moon's golden number
+ \newcount\x % Temp
+ \newcount\m % Temp for modulus
+ \diy=\day \advance\diy by \ifcase\month % Jan 1 == 0
+ -1\or -1\or 30\or 58\or 89\or 119\or 150\or % Jan .. Jun
+ 180\or 211\or 241\or 272\or 303\or 333\fi % Jul .. Dec
+% if ((month > 2) && ((year % 4 == 0) &&
+% ((year % 400 == 0) || (year % 100 != 0))))
+% diy++; /* Leapyear fixup */
+ \ifnum \month>2
+ \x=\year \m=\x \divide\m by 4 \multiply\m by 4 \advance\x by -\m
+ \ifnum \x=0 % month > 2 and maybe leapyear
+ \x=\year \m=\x \divide\m by 400 \multiply\m by 400 \advance\x by -\m
+ \ifnum \x=0 % 2000 is a leap year
+ \advance\diy by 1 % so it's one day later
+ \else % not 2000, check other '00's
+ \x=\year \m=\x \divide\m by 100 \multiply\m by 100 \advance\x by -\m
+ \ifnum \x>0 % not some other '00' year
+ \advance\diy by 1 % it's still one day later
+ \fi % not odd century
+ \fi % not 2000-type century
+ \fi % not leapish year
+ \fi % not march or later
+% cent = (year / 100) + 1; /* Century number */
+% golden = (year % 19) + 1; /* Golden number */
+ \cent=\year \divide\cent by 100 \advance\cent by 1
+ \golden=\year
+ \m=\year \divide\m by 19 \multiply\m by 19 \advance\golden by -\m
+ \advance\golden by 1
+% epact = ((11 * golden) + 20 /* Golden number */
+% + (((8 * cent) + 5) / 25) - 5 /* 400 year cycle */
+% - (((3 * cent) / 4) - 12)) % 30;/* Leap year correction */
+ \epact=11 \multiply\epact by \golden
+ \advance\epact by 20
+ \x=8 \multiply\x by \cent \advance\x by 5
+ \divide\x by 25 \advance\x by -5
+ \advance\epact by \x
+ \x=3 \multiply\x by \cent \divide\x by 4 \advance\x by -12
+ \advance\epact by -\x
+ \m=\epact \divide\m by 30 \multiply\m by 30 \advance\epact by -\m
+% if (epact <= 0)
+% epact += 30; /* Age range is 1 .. 30 */
+% if ((epact == 25 && golden > 11) || epact == 24)
+% epact++;
+ \ifnum \epact<0
+ \advance\epact by 30
+ \fi
+ \ifnum \epact=25
+ \ifnum \golden>11
+ \advance \epact by 1
+ \fi
+ \else
+ \ifnum \epact=24
+ \advance \epact by 1
+ \fi
+ \fi
+%
+% Calculate the phase, using the magic numbers defined above.
+% Note that phase may be equal to 8 (== 0) on two days of the year
+% due to the way the algorithm was implemented.
+% phase = (((((diy + epact) * 6) + 11) % 177) / 22) & 7;
+%
+ \x=\diy \advance\x by \epact \multiply\x by 6 \advance\x by 11
+ \m=\x \divide\m by 177 \multiply\m by 177 \advance\x by -\m
+ \divide\x by 22
+ \ifcase\x new\or waxing crescent\or in its first quarter\or
+ waxing gibbous\or full\or waning gibbous\or
+ in its last quarter\or waning crescent\or new\fi
+}