33 lines
796 B
YAML
33 lines
796 B
YAML
# Common method definitions for the Ruby Holiday gem.
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# Updated 2008-11-21.
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---
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methods:
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easter: |
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# Get the date of Easter in a given year.
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#
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# +year+ must be a valid Gregorian year.
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#
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# Returns a Date object.
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#--
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# from http://snippets.dzone.com/posts/show/765
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# TODO: check year to ensure Gregorian
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def self.easter(year)
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y = year
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a = y % 19
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b = y / 100
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c = y % 100
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d = b / 4
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e = b % 4
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f = (b + 8) / 25
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g = (b - f + 1) / 3
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h = (19 * a + b - d - g + 15) % 30
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i = c / 4
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k = c % 4
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l = (32 + 2 * e + 2 * i - h - k) % 7
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m = (a + 11 * h + 22 * l) / 451
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month = (h + l - 7 * m + 114) / 31
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day = ((h + l - 7 * m + 114) % 31) + 1
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Date.civil(year, month, day)
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end
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