* lib/date.rb, lib/date/format.rb: introduced some constants

	  (for internal use) and aliases (minute and second).

	* sample/cal.rb: trivial adjustments.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@14904 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 56 insertions, 29 deletions

diff --git a/lib/date.rb b/lib/date.rb
index ce24802371..bc75b198af 100644
--- a/lib/date.rb
+++ b/lib/date.rb
@@ -1,12 +1,12 @@
 #
 # date.rb - date and time library
 #
-# Author: Tadayoshi Funaba 1998-2007
+# Author: Tadayoshi Funaba 1998-2008
 #
 # Documentation: William Webber <william@williamwebber.com>
 #
 #--
-# $Id: date.rb,v 2.34 2007-12-30 21:45:27+09 tadf Exp $
+# $Id: date.rb,v 2.35 2008-01-06 08:42:17+09 tadf Exp $
 #++
 #
 # == Overview
@@ -313,7 +313,20 @@ class Date
   # Gregorian calendar.
   GREGORIAN = -Infinity.new
 
-  UNIXEPOCH = 2440588 # 1970-01-01 :nodoc:
+  HALF_DAYS_IN_DAY       = Rational(1, 2) # :nodoc:
+  HOURS_IN_DAY           = Rational(1, 24) # :nodoc:
+  MINUTES_IN_DAY         = Rational(1, 1440) # :nodoc:
+  SECONDS_IN_DAY         = Rational(1, 86400) # :nodoc:
+  MILLISECONDS_IN_DAY    = Rational(1, 86400*10**3) # :nodoc:
+  NANOSECONDS_IN_DAY     = Rational(1, 86400*10**9) # :nodoc:
+  MILLISECONDS_IN_SECOND = Rational(1, 10**3) # :nodoc:
+  NANOSECONDS_IN_SECOND  = Rational(1, 10**9) # :nodoc:
+
+  MJD_EPOCH_IN_AJD       = Rational(4800001, 2) # 1858-11-17 # :nodoc:
+  UNIX_EPOCH_IN_AJD      = Rational(4881175, 2) # 1970-01-01 # :nodoc:
+  MJD_EPOCH_IN_CJD       = 2400001 # :nodoc:
+  UNIX_EPOCH_IN_CJD      = 2440588 # :nodoc:
+  LD_EPOCH_IN_CJD        = 2299160 # :nodoc:
 
   # Does a given Julian Day Number fall inside the old-style (Julian)
   # calendar?
@@ -476,7 +489,7 @@ class Date
   #
   # Returns the (civil) Julian Day Number as [day_number,
   # fraction] where +fraction+ is always 1/2.
-  def self.ajd_to_jd(ajd, of=0) (ajd + of + 1.to_r/2).divmod(1) end
+  def self.ajd_to_jd(ajd, of=0) (ajd + of + HALF_DAYS_IN_DAY).divmod(1) end
 
   # Convert a (civil) Julian Day Number to an Astronomical Julian
   # Day Number.
@@ -487,46 +500,54 @@ class Date
   #
   # Returns the Astronomical Julian Day Number as a single
   # numeric value.
-  def self.jd_to_ajd(jd, fr, of=0) jd + fr - of - 1.to_r/2 end
+  def self.jd_to_ajd(jd, fr, of=0) jd + fr - of - HALF_DAYS_IN_DAY end
 
   # Convert a fractional day +fr+ to [hours, minutes, seconds,
   # fraction_of_a_second]
   def self.day_fraction_to_time(fr)
-    h,   fr = fr.divmod(1.to_r/24)
-    min, fr = fr.divmod(1.to_r/1440)
-    s,   fr = fr.divmod(1.to_r/86400)
+    h,   fr = fr.divmod(HOURS_IN_DAY)
+    min, fr = fr.divmod(MINUTES_IN_DAY)
+    s,   fr = fr.divmod(SECONDS_IN_DAY)
     return h, min, s, fr
   end
 
   # Convert an +h+ hour, +min+ minutes, +s+ seconds period
   # to a fractional day.
-  def self.time_to_day_fraction(h, min, s)
-    h.to_r/24 + min.to_r/1440 + s.to_r/86400
+  begin
+    Rational(Rational(1, 2), 2) # a challenge
+
+    def self.time_to_day_fraction(h, min, s)
+      Rational(h, 24) + Rational(min, 1440) + Rational(s, 86400)
+    end
+  rescue
+    def self.time_to_day_fraction(h, min, s)
+      h.to_r/24 + min.to_r/1440 + s.to_r/86400
+    end
   end
 
   # Convert an Astronomical Modified Julian Day Number to an
   # Astronomical Julian Day Number.
-  def self.amjd_to_ajd(amjd) amjd + 4800001.to_r/2 end
+  def self.amjd_to_ajd(amjd) amjd + MJD_EPOCH_IN_AJD end
 
   # Convert an Astronomical Julian Day Number to an
   # Astronomical Modified Julian Day Number.
-  def self.ajd_to_amjd(ajd) ajd - 4800001.to_r/2 end
+  def self.ajd_to_amjd(ajd) ajd - MJD_EPOCH_IN_AJD end
 
   # Convert a Modified Julian Day Number to a Julian
   # Day Number.
-  def self.mjd_to_jd(mjd) mjd + 2400001 end
+  def self.mjd_to_jd(mjd) mjd + MJD_EPOCH_IN_CJD end
 
   # Convert a Julian Day Number to a Modified Julian Day
   # Number.
-  def self.jd_to_mjd(jd) jd - 2400001 end
+  def self.jd_to_mjd(jd) jd - MJD_EPOCH_IN_CJD end
 
   # Convert a count of the number of days since the adoption
   # of the Gregorian Calendar (in Italy) to a Julian Day Number.
-  def self.ld_to_jd(ld) ld + 2299160 end
+  def self.ld_to_jd(ld) ld + LD_EPOCH_IN_CJD end
 
   # Convert a Julian Day Number to the number of days since
   # the adoption of the Gregorian Calendar (in Italy).
-  def self.jd_to_ld(jd) jd - 2299160 end
+  def self.jd_to_ld(jd) jd - LD_EPOCH_IN_CJD end
 
   # Convert a Julian Day Number to the day of the week.
   #
@@ -768,7 +789,7 @@ class Date
       h,   fr = fr.divmod(3600)
       min, fr = fr.divmod(60)
       s,   fr = fr.divmod(1)
-      elem[:jd] = UNIXEPOCH + d
+      elem[:jd] = UNIX_EPOCH_IN_CJD + d
       elem[:hour] = h
       elem[:min] = min
       elem[:sec] = s
@@ -1096,7 +1117,14 @@ class Date
   # I do NOT recommend you to use this method.
   def sec_fraction() time[3] end
 
+=begin
+  alias_method :minute, :min
+  alias_method :second, :sec
+  alias_method :second_fraction, :sec_fraction
+=end
+
   private :hour, :min, :sec, :sec_fraction
+#	  :minute, :second, :second_fraction
 
   def zone() strftime('%:z') end
 
@@ -1181,7 +1209,7 @@ class Date
 
   def new_offset(of=0)
     if String === of
-      of = (self.class.zone_to_diff(of) || 0).to_r/86400
+      of = Rational(zone_to_diff(of) || 0, 86400)
     end
     self.class.new!(@ajd, of, @sg)
   end
@@ -1437,7 +1465,7 @@ class DateTime < Date
       raise ArgumentError, 'invalid date'
     end
     if String === of
-      of = (zone_to_diff(of) || 0).to_r/86400
+      of = Rational(zone_to_diff(of) || 0, 86400)
     end
     new!(jd_to_ajd(jd, fr, of), of, sg)
   end
@@ -1462,7 +1490,7 @@ class DateTime < Date
       raise ArgumentError, 'invalid date'
     end
     if String === of
-      of = (zone_to_diff(of) || 0).to_r/86400
+      of = Rational(zone_to_diff(of) || 0, 86400)
     end
     new!(jd_to_ajd(jd, fr, of), of, sg)
   end
@@ -1487,7 +1515,7 @@ class DateTime < Date
       raise ArgumentError, 'invalid date'
     end
     if String === of
-      of = (zone_to_diff(of) || 0).to_r/86400
+      of = Rational(zone_to_diff(of) || 0, 86400)
     end
     new!(jd_to_ajd(jd, fr, of), of, sg)
   end
@@ -1515,7 +1543,7 @@ class DateTime < Date
       raise ArgumentError, 'invalid date'
     end
     if String === of
-      of = (zone_to_diff(of) || 0).to_r/86400
+      of = Rational(zone_to_diff(of) || 0, 86400)
     end
     new!(jd_to_ajd(jd, fr, of), of, sg)
   end
@@ -1526,7 +1554,7 @@ class DateTime < Date
       raise ArgumentError, 'invalid date'
     end
     if String === of
-      of = (zone_to_diff(of) || 0).to_r/86400
+      of = Rational(zone_to_diff(of) || 0, 86400)
     end
     new!(jd_to_ajd(jd, fr, of), of, sg)
   end
@@ -1540,10 +1568,8 @@ class DateTime < Date
 	   (fr = valid_time_frags?(elem))
       raise ArgumentError, 'invalid date'
     end
-    sf = (elem[:sec_fraction] || 0)
-    fr += sf/86400
-    of = (elem[:offset] || 0)
-    of = of.to_r/86400
+    fr += (elem[:sec_fraction] || 0) / 86400
+    of = Rational(elem[:offset] || 0, 86400)
     new!(jd_to_ajd(jd, fr, of), of, sg)
   end
 
@@ -1589,6 +1615,7 @@ class DateTime < Date
   end
 
   public :hour, :min, :sec, :sec_fraction, :zone, :offset, :new_offset
+#	 :minute, :second, :second_fraction
 
 end
 
@@ -1604,8 +1631,8 @@ class Time
   def to_datetime
     jd = DateTime.civil_to_jd(year, mon, mday, DateTime::ITALY)
     fr = DateTime.time_to_day_fraction(hour, min, [sec, 59].min) +
-	 usec.to_r/86400000000
-    of = utc_offset.to_r/86400
+      Rational(usec, 86400_000_000)
+    of = Rational(utc_offset, 86400)
     DateTime.new!(DateTime.jd_to_ajd(jd, fr, of), of, DateTime::ITALY)
   end