julian.csh

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 ```# Calculate the Julian day number for the specified date. # Based on algorithms published in Computer Language magazine, # December, 1990. Used with permission. proc julian(month, day, year) # The Julian day number is the number of days between noon GMT # Jan 1, 4713 BC and that date. (Years B.C. are negative.) local a, b, year_corr, Month, i set Month = January February March April May June ^ July August September October November December if (year == '') then local dt set dt = `dt` @ year = \$dt:3 if (day == '') then @ day = month == '' ? \$dt:2 : month @ month = \$dt:1 end end if (month !~ '[0-9]*') then @ month = "\$lower(month)*" for i = 0 to 11 do if (lower(Month[i]) =~ month) break end @ month = i + 1 end if (month < 1 || month > 12 || year < -4713 || year > 2900) then echo -2 julian: Invalid Date return -1 end # Correct for negative year. if (year < 0) then @ year++ @ year_corr = 1 @ b = 1 else @ year_corr = b = 0 end if (month <= 2) then @ year-- @ month += 12 end # Cope with the Gregorian calendar reform if (year * 10000 + month * 100 + day > 15821015) then @ a = year//100 @ b = 2 - a + a//4 end @ a = floor(365.25 * year - year_corr) + ^ floor(30.6001 * (month + 1)) + day + 1720994 + b # 4713 BC was not a leap year. if (a < 59) @ a++ return a end julian \$argv ```