synchronized with date2 3.5.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@5495 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

4 files changed, 207 insertions, 156 deletions

diff --git a/ChangeLog b/ChangeLog
index 095232fe4d..82cd4949b1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+Mon Jan 19 07:09:20 2004  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* lib/date.rb: zone was wrong when it was behind UTC.
+	  Thanks Mark J. Reed.
+
+	* lib/date/format.rb: %z is now always replaced by four digits
+	  with a leading plus or minus sign.
+
+	* sample/cal.rb: added a class, anyway.
+
 Sun Jan 18 20:47:35 2004  WATANABE Hirofumi  <eban@ruby-lang.org>
 
 	* ruby.c: use translate_char() on Cygwin.
diff --git a/lib/date.rb b/lib/date.rb
index 21e35a6660..0747da1295 100644
--- a/lib/date.rb
+++ b/lib/date.rb
@@ -1,20 +1,20 @@
-# 
+#
 # date.rb - date and time library
 #
-# Author: Tadayoshi Funaba 1998-2002
+# Author: Tadayoshi Funaba 1998-2004
 #
 # Documentation: William Webber <william@williamwebber.com>
 #
 #--
-# $Id: date.rb,v 2.8 2002-06-08 00:39:51+09 tadf Exp $
+# $Id: date.rb,v 2.11 2004-01-19 04:56:12+09 tadf Exp $
 #++
 #
 # == Overview
 #
 # This file provides two classes for working with
 # dates and times.
-# 
-# The first class, Date, represents dates.  
+#
+# The first class, Date, represents dates. 
 # It works with years, months, weeks, and days.
 # See the Date class documentation for more details.
 #
@@ -28,11 +28,11 @@
 # In common usage, the date is reckoned in years since or
 # before the Common Era (CE/BCE, also known as AD/BC), then
 # as a month and day-of-the-month within the current year.
-# This is known as the *Civil* *Date*, and abbrevated 
+# This is known as the *Civil* *Date*, and abbrevated
 # as +civil+ in the Date class.
 #
-# Instead of year, month-of-the-year,  and day-of-the-month, 
-# the date can also be reckoned in terms of year and 
+# Instead of year, month-of-the-year,  and day-of-the-month,
+# the date can also be reckoned in terms of year and
 # day-of-the-year.  This is known as the *Ordinal* *Date*,
 # and is abbreviated as +ordinal+ in the Date class.  (Note
 # that referring to this as the Julian date is incorrect.)
@@ -58,7 +58,7 @@
 # Date class as the *Astronomical* *Julian* *Day* *Number*, and
 # abbreviated as +ajd+.  In the Date class, the Astronomical
 # Julian Day Number includes fractional days.
-# 
+#
 # Another absolute day count is the *Modified* *Julian* *Day*
 # *Number*, which takes November 17, 1858 as its initial day.
 # This is abbreviated as +mjd+ in the Date class.  There
@@ -80,7 +80,7 @@
 # The standard civil year is 365 days long.  However, the
 # solar year is fractionally longer than this.  To account
 # for this, a *leap* *year* is occasionally inserted.  This
-# is a year with 366 days, the extra day falling on February 29.  
+# is a year with 366 days, the extra day falling on February 29. 
 # In the early days of the civil calendar, every fourth
 # year without exception was a leap year.  This way of
 # reckoning leap years is the *Julian* *Calendar*.
@@ -94,7 +94,7 @@
 #
 # The Gregorian Calendar was introduced at different times
 # in different regions.  The day on which it was introduced
-# for a particular region is the *Day* *of* *Calendar* 
+# for a particular region is the *Day* *of* *Calendar*
 # *Reform* for that region.  This is abbreviated as +sg+
 # (for Start of Gregorian calendar) in the Date class.
 #
@@ -103,24 +103,24 @@
 # the Day of Calendar Reform for Italy and most Catholic
 # countries.  The second is September 14, 1752, which was
 # the Day of Calendar Reform for England and its colonies
-# (including what is now the United States).  These two 
+# (including what is now the United States).  These two
 # dates are available as the constants Date::ITALY and
 # Date::ENGLAND, respectively.  (By comparison, Germany and
 # Holland, less Catholic than Italy but less stubborn than
 # England, changed over in 1698; Sweden in 1753; Russia not
 # till 1918, after the Revolution; and Greece in 1923.  Many
 # Orthodox churches still use the Julian Calendar.  A complete
-# list of Days of Calendar Reform can be found at 
+# list of Days of Calendar Reform can be found at
 # http://www.polysyllabic.com/GregConv.html.)
 #
 # Switching from the Julian to the Gregorian calendar
 # involved skipping a number of days to make up for the
 # accumulated lag, and the later the switch was (or is)
 # done, the more days need to be skipped.  So in 1582 in Italy,
-# 4th October was followed by 15th October, skipping 10 days; in 1752 
+# 4th October was followed by 15th October, skipping 10 days; in 1752
 # in England, 2nd September was followed by 14th September, skipping
-# 11 days; and if I decided to switch from Julian to Gregorian 
-# Calendar this midnight, I would go from 27th July 2003 (Julian) 
+# 11 days; and if I decided to switch from Julian to Gregorian
+# Calendar this midnight, I would go from 27th July 2003 (Julian)
 # today to 10th August 2003 (Gregorian) tomorrow, skipping
 # 13 days.  The Date class is aware of this gap, and a supposed
 # date that would fall in the middle of it is regarded as invalid.
@@ -148,13 +148,13 @@
 # of time zones.  Time zones are represented as an offset
 # from UTC, as a fraction of a day.  This offset is the
 # how much local time is later (or earlier) than UTC.
-# UTC offset 0 is centred on England (also known as GMT).  
+# UTC offset 0 is centred on England (also known as GMT). 
 # As you travel east, the offset increases until you
 # reach the dateline in the middle of the Pacific Ocean;
 # as you travel west, the offset decreases.  This offset
 # is abbreviated as +of+ in the Date class.
 #
-# This simple representation of time zones does not take 
+# This simple representation of time zones does not take
 # into account the common practice of Daylight Savings
 # Time or Summer Time.
 #
@@ -201,7 +201,7 @@ require 'date/format'
 # See the documentation to the file date.rb for an overview.
 #
 # Internally, the date is represented as an Astronomical
-# Julian Day Number, +ajd+.  The Day of Calendar Reform, +sg+, is 
+# Julian Day Number, +ajd+.  The Day of Calendar Reform, +sg+, is
 # also stored, for conversions to other date formats.  (There
 # is also an +of+ field for a time zone offset, but this
 # is only for the use of the DateTime subclass.)
@@ -217,7 +217,7 @@ require 'date/format'
 # Date objects are immutable once created.
 #
 # Once a Date has been created, date values
-# can be retrieved for the different date formats supported 
+# can be retrieved for the different date formats supported
 # using instance methods.  For instance, #mon() gives the
 # Civil month, #cwday() gives the Commercial day of the week,
 # and #yday() gives the Ordinal day of the year.  Date values
@@ -237,7 +237,7 @@ class Date
   MONTHNAMES = [nil] + %w(January February March April May June July
 			  August September October November December)
 
-  # Full names of days of the week, in English.  Days of the week 
+  # Full names of days of the week, in English.  Days of the week
   # count from 0 to 6 (except in the commercial week); a day's numerical
   # represenation indexed into this array gives the name of that day.
   DAYNAMES = %w(Sunday Monday Tuesday Wednesday Thursday Friday Saturday)
@@ -312,7 +312,7 @@ class Date
   # the Julian Day Number. +sg+ specifies the Day of
   # Calendar Reform.
   #
-  # Returns the corresponding [year, month, day_of_month] 
+  # Returns the corresponding [year, month, day_of_month]
   # as a three-element array.
   def self.jd_to_civil(jd, sg=GREGORIAN)
     if os?(jd, sg)
@@ -351,7 +351,7 @@ class Date
   # +jd+ is the Julian Day Number to convert.
   # +sg+ specifies the Day of Calendar Reform.
   #
-  # Returns the corresponding Ordinal Date as 
+  # Returns the corresponding Ordinal Date as
   # [year, day_of_year]
   def self.jd_to_ordinal(jd, sg=GREGORIAN)
     y = jd_to_civil(jd, sg)[0]
@@ -378,7 +378,7 @@ class Date
 
   # Convert a Commercial Date to a Julian Day Number.
   #
-  # +y+, +w+, and +d+ are the (commercial) year, week of the year, 
+  # +y+, +w+, and +d+ are the (commercial) year, week of the year,
   # and day of the week of the Commercial Date to convert.
   # +sg+ specifies the Day of Calendar Reform.
   def self.commercial_to_jd(y, w, d, ns=GREGORIAN)
@@ -405,7 +405,7 @@ class Date
   # Convert an Astronomical Julian Day Number to a (civil) Julian
   # Day Number.
   #
-  # +ajd+ is the Astronomical Julian Day Number to convert.  
+  # +ajd+ is the Astronomical Julian Day Number to convert. 
   # +of+ is the offset from UTC as a fraction of a day (defaults to 0).
   #
   # Returns the (civil) Julian Day Number as [day_number,
@@ -416,10 +416,10 @@ class Date
   # Day Number.
   #
   # +jd+ is the Julian Day Number to convert, and +fr+ is a
-  # fractional day.  
+  # fractional day. 
   # +of+ is the offset from UTC as a fraction of a day (defaults to 0).
   #
-  # Returns the Astronomical Julian Day Number as a single 
+  # 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
 
@@ -438,7 +438,7 @@ class Date
     h.to_r/24 + min.to_r/1440 + s.to_r/86400
   end
 
-  # Convert an Astronomical Modified Julian Day Number to an 
+  # 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
 
@@ -450,7 +450,7 @@ class Date
   # Day Number.
   def self.mjd_to_jd(mjd) mjd + 2400001 end
 
-  # Convert a Julian Day Number to a Modified Julian Day 
+  # Convert a Julian Day Number to a Modified Julian Day
   # Number.
   def self.jd_to_mjd(jd) jd - 2400001 end
 
@@ -490,7 +490,7 @@ class Date
   # Create a new Date object from a Julian Day Number.
   #
   # +jd+ is the Julian Day Number; if not specified, it defaults to
-  # 0.  
+  # 0. 
   # +sg+ specifies the Day of Calendar Reform.
   def self.jd(jd=0, sg=ITALY)
     jd = valid_jd?(jd, sg)
@@ -504,8 +504,8 @@ class Date
   # +d+ can be a negative number, in which case it counts backwards
   # from the end of the year (-1 being the last day of the year).
   # No year wraparound is performed, however, so valid values of
-  # +d+ are -365 .. -1, 1 .. 365 on a non-leap-year, 
-  # -366 .. -1, 1 .. 366 on a leap year.  
+  # +d+ are -365 .. -1, 1 .. 365 on a non-leap-year,
+  # -366 .. -1, 1 .. 366 on a leap year. 
   # A date falling in the period skipped in the Day of Calendar Reform
   # adjustment is not valid.
   #
@@ -541,15 +541,15 @@ class Date
     new0(jd_to_ajd(jd, 0, 0), 0, sg)
   end
 
-  # Do year +y+, month +m+, and day-of-month +d+ make a 
-  # valid Civil Date?  Returns the corresponding Julian 
+  # Do year +y+, month +m+, and day-of-month +d+ make a
+  # valid Civil Date?  Returns the corresponding Julian
   # Day Number if they do, nil if they don't.
   #
   # +m+ and +d+ can be negative, in which case they count
   # backwards from the end of the year and the end of the
   # month respectively.  No wraparound is performed, however,
   # and invalid values cause an ArgumentError to be raised.
-  # A date falling in the period skipped in the Day of Calendar 
+  # A date falling in the period skipped in the Day of Calendar
   # Reform adjustment is not valid.
   #
   # +sg+ specifies the Day of Calendar Reform.
@@ -580,7 +580,7 @@ class Date
   # backwards from the end of the year and the end of the
   # month respectively.  No wraparound is performed, however,
   # and invalid values cause an ArgumentError to be raised.
-  # can be negative 
+  # can be negative
   #
   # +y+ defaults to -4712, +m+ to 1, and +d+ to 1; this is
   # Julian Day Number day 0.
@@ -605,7 +605,7 @@ class Date
   # backwards from the end of the year and the end of the
   # week respectively.  No wraparound is performed, however,
   # and invalid values cause an ArgumentError to be raised.
-  # A date falling in the period skipped in the Day of Calendar 
+  # A date falling in the period skipped in the Day of Calendar
   # Reform adjustment is not valid.
   #
   # +sg+ specifies the Day of Calendar Reform.
@@ -659,7 +659,7 @@ class Date
   # according to a specified format.
   #
   # +str+ is a String holding a date representation.
-  # +fmt+ is the format that the date is in.  See 
+  # +fmt+ is the format that the date is in.  See
   # date/format.rb for details on supported formats.
   #
   # The default +str+ is '-4712-01-01', and the default
@@ -678,7 +678,7 @@ class Date
   # Create a new Date object by parsing from a String,
   # without specifying the format.
   #
-  # +str+ is a String holding a date representation.  
+  # +str+ is a String holding a date representation. 
   # +comp+ specifies whether to interpret 2-digit years
   # as 19XX (>= 69) or 20XX (< 69); the default is not to.
   # The method will attempt to parse a date from the String
@@ -723,7 +723,7 @@ class Date
 
   # *NOTE* this is the documentation for the method new0().  If
   # you are reading this as the documentation for new(), that is
-  # because rdoc doesn't fully support the aliasing of the 
+  # because rdoc doesn't fully support the aliasing of the
   # initialize() method.
   # new() is in
   # fact an alias for #civil(): read the documentation for that
@@ -731,9 +731,9 @@ class Date
   #
   # Create a new Date object.
   #
-  # +ajd+ is the Astronomical Julian Day Number. 
+  # +ajd+ is the Astronomical Julian Day Number.
   # +of+ is the offset from UTC as a fraction of a day.
-  # Both default to 0. 
+  # Both default to 0.
   #
   # +sg+ specifies the Day of Calendar Reform to use for this
   # Date object.
@@ -817,13 +817,7 @@ class Date
 
   private :hour, :min, :sec, :sec_fraction
 
-  def zone
-    ['Z',
-      format('%+.2d%02d',
-	     (@of     / (1.to_r/24)).to_i,
-	     (@of.abs % (1.to_r/24) / (1.to_r/1440)).to_i)
-    ][@of<=>0]
-  end
+  def zone() strftime('%Z') end
 
   private :zone
 
@@ -921,7 +915,7 @@ class Date
 
   # Compare this date with another date.
   #
-  # +other+ can also be a Numeric value, in which case it is 
+  # +other+ can also be a Numeric value, in which case it is
   # interpreted as an Astronomical Julian Day Number.
   #
   # Comparison is by Astronomical Julian Day Number, including
@@ -975,7 +969,7 @@ class Date
   def << (n) self >> -n end
 
   # Step the current date forward +step+ days at a
-  # time (or backward, if +step+ is negative) until 
+  # time (or backward, if +step+ is negative) until
   # we reach +limit+ (inclusive), yielding the resultant
   # date at each step.
   def step(limit, step)  # :yield: date
@@ -991,13 +985,13 @@ class Date
   # Step forward one day at a time until we reach +max+
   # (inclusive), yielding each date as we go.
   def upto(max, &block)  # :yield: date
-      step(max, +1, &block) 
-  end 
+      step(max, +1, &block)
+  end
 
   # Step backward one day at a time until we reach +min+
   # (inclusive), yielding each date as we go.
   def downto(min, &block) # :yield: date
-      step(min, -1, &block) 
+      step(min, -1, &block)
   end
 
   # Return a new Date one day after this one.
@@ -1057,7 +1051,7 @@ end
 #
 # Get the hour-of-the-day of the time.  This is given
 # using the 24-hour clock, counting from midnight.  The first
-# hour after midnight is hour 0; the last hour of the day is 
+# hour after midnight is hour 0; the last hour of the day is
 # hour 23.
 #
 # === min()
@@ -1165,7 +1159,7 @@ class DateTime < Date
   # +of+ is the offset from UTC as a fraction of a day (defaults to 0).
   # +sg+ specifies the Day of Calendar Reform.
   #
-  # +y+ defaults to -4712, +m+ to 1, and +d+ to 1; this is Julian Day 
+  # +y+ defaults to -4712, +m+ to 1, and +d+ to 1; this is Julian Day
   # Number day 0.  The time values default to 0.
   def self.civil(y=-4712, m=1, d=1, h=0, min=0, s=0, of=0, sg=ITALY)
     unless (jd = valid_civil?(y, m, d, sg)) and
@@ -1221,7 +1215,7 @@ class DateTime < Date
   # according to a specified format.
   #
   # +str+ is a String holding a date-time representation.
-  # +fmt+ is the format that the date-time is in.  See 
+  # +fmt+ is the format that the date-time is in.  See
   # date/format.rb for details on supported formats.
   #
   # The default +str+ is '-4712-01-01T00:00:00Z', and the default
@@ -1239,7 +1233,7 @@ class DateTime < Date
   # Create a new DateTime object by parsing from a String,
   # without specifying the format.
   #
-  # +str+ is a String holding a date-time representation.  
+  # +str+ is a String holding a date-time representation. 
   # +comp+ specifies whether to interpret 2-digit years
   # as 19XX (>= 69) or 20XX (< 69); the default is not to.
   # The method will attempt to parse a date-time from the String
@@ -1266,9 +1260,7 @@ class DateTime < Date
     a = i.to_a[0..5].reverse
     jd = civil_to_jd(*(a[0,3] << sg))
     fr = time_to_day_fraction(*(a[3,3])) + i.usec.to_r/86400000000
-    d = Time.gm(*i.to_a).to_i - i.to_i
-    d += d / d.abs if d.nonzero?
-    of = (d / 60).to_r/1440
+    of = i.utc_offset.to_r/86400
     new0(jd_to_ajd(jd, fr, of), of, sg)
   end
 
diff --git a/lib/date/format.rb b/lib/date/format.rb
index f00f60ab47..d3d8d17511 100644
--- a/lib/date/format.rb
+++ b/lib/date/format.rb
@@ -1,5 +1,5 @@
-# format.rb: Written by Tadayoshi Funaba 1999-2003
-# $Id: format.rb,v 2.9 2003-04-19 19:19:35+09 tadf Exp $
+# format.rb: Written by Tadayoshi Funaba 1999-2004
+# $Id: format.rb,v 2.12 2004-01-19 05:43:28+09 tadf Exp $
 
 class Date
 
@@ -501,8 +501,14 @@ class Date
       when '%x'; o << strftime('%m/%d/%y')
       when '%Y'; o << '%.4d' %  year
       when '%y'; o << '%02d' % (year % 100)
-      when '%Z'; o << zone
-      when '%z'; o << zone					# ID
+      when '%Z'; o << (if offset.zero? then 'Z' else strftime('%z') end)
+      when '%z'							# ID
+	o << if offset < 0 then '-' else '+' end
+	of = offset.abs
+	hh, fr = of.divmod(1.to_r/24)
+	mm = fr / (1.to_r/1440)
+	o << '%02d' % hh
+	o << '%02d' % mm
       when '%%'; o << '%'
       when '%+'; o << strftime('%a %b %e %H:%M:%S %Z %Y')	# TZ
       when '%1'; o <<   '%d' % jd
diff --git a/sample/cal.rb b/sample/cal.rb
index e17c5e2a3e..fa20352f71 100644
--- a/sample/cal.rb
+++ b/sample/cal.rb
@@ -1,111 +1,154 @@
 #! /usr/bin/env ruby
 
-# cal.rb: Written by Tadayoshi Funaba 1998-2002
-# $Id: cal.rb,v 2.4 2002-06-08 00:40:29+09 tadf Exp $
+# cal.rb: Written by Tadayoshi Funaba 1998-2004
+# $Id: cal.rb,v 2.7 2004-01-10 23:52:51+09 tadf Exp $
 
 require 'date'
-require 'getopts'
-
-$tab =
-{
-  'cn' => true,    # China
-  'de' => 2342032, # Germany (protestant states)
-  'dk' => 2342032, # Denmark
-  'es' => 2299161, # Spain
-  'fi' => 2361390, # Finland
-  'fr' => 2299227, # France
-  'gb' => 2361222, # United Kingdom
-  'gr' => 2423868, # Greece
-  'hu' => 2301004, # Hungary
-  'it' => 2299161, # Italy
-  'jp' => true,    # Japan
-  'no' => 2342032, # Norway
-  'pl' => 2299161, # Poland
-  'pt' => 2299161, # Portugal
-  'ru' => 2421639, # Russia
-  'se' => 2361390, # Sweden
-  'us' => 2361222, # United States
-  'os' => false,   # (old style)
-  'ns' => true     # (new style)
-}
-
-$cc = 'gb'
-
-def usage
-  warn 'usage: cal [-c iso3166] [-jmty] [[month] year]'
-  exit 1
-end
-
-def pict(y, m, sg)
-  d = (1..31).detect{|d| Date.valid_date?(y, m, d, sg)}
-  fi = Date.new(y, m, d, sg)
-  fi -= (fi.jd - $k + 1) % 7
 
-  ve  = (fi..fi +  6).collect{|cu|
-    %w(S M Tu W Th F S)[cu.wday]
-  }
-  ve += (fi..fi + 41).collect{|cu|
-    if cu.mon == m then cu.send($da) end.to_s
+class Cal
+
+  START =
+    {
+    'cn' => true,    # China
+    'de' => 2342032, # Germany (protestant states)
+    'dk' => 2342032, # Denmark
+    'es' => 2299161, # Spain
+    'fi' => 2361390, # Finland
+    'fr' => 2299227, # France
+    'gb' => 2361222, # United Kingdom
+    'gr' => 2423868, # Greece
+    'hu' => 2301004, # Hungary
+    'it' => 2299161, # Italy
+    'jp' => true,    # Japan
+    'no' => 2342032, # Norway
+    'pl' => 2299161, # Poland
+    'pt' => 2299161, # Portugal
+    'ru' => 2421639, # Russia
+    'se' => 2361390, # Sweden
+    'us' => 2361222, # United States
+    'os' => false,   # (old style)
+    'ns' => true     # (new style)
   }
 
-  ve = ve.collect{|e| e.rjust($dw)}
-
-  gr = group(ve, 7)
-  gr = trans(gr) if $OPT_t
-  ta = gr.collect{|xs| xs.join(' ')}
-
-  ca = %w(January February March April May June July
-	  August September October November December)[m - 1]
-  ca = ca + ' ' + y.to_s if not $OPT_y
-  ca = ca.center($mw)
-
-  ta.unshift(ca)
-end
+  DEFAULT_START = 'gb'
+
+  def initialize
+    opt_j; opt_m; opt_t; opt_y; opt_c
+  end
+
+  def opt_j(flag=false) @opt_j = flag end
+  def opt_m(flag=false) @opt_m = flag end
+  def opt_t(flag=false) @opt_t = flag end
+  def opt_y(flag=false) @opt_y = flag end
+
+  def opt_c(arg=DEFAULT_START) @start = START[arg] end
+
+  def set_params
+    @dw = if @opt_j then 3 else 2 end
+    @mw = (@dw + 1) * 7 - 1
+    @mn = if @opt_j then 2 else 3 end
+    @tw = (@mw + 2) * @mn - 2
+    @k  = if @opt_m then 1 else 0 end
+    @da = if @opt_j then :yday else :mday end
+  end
+
+  def pict(y, m)
+    d = (1..31).detect{|d| Date.valid_date?(y, m, d, @start)}
+    fi = Date.new(y, m, d, @start)
+    fi -= (fi.jd - @k + 1) % 7
+
+    ve  = (fi..fi +  6).collect{|cu|
+      %w(S M Tu W Th F S)[cu.wday]
+    }
+    ve += (fi..fi + 41).collect{|cu|
+      if cu.mon == m then cu.send(@da) end.to_s
+    }
+
+    ve = ve.collect{|e| e.rjust(@dw)}
+
+    gr = group(ve, 7)
+    gr = trans(gr) if @opt_t
+    ta = gr.collect{|xs| xs.join(' ')}
+
+    ca = %w(January February March April May June July
+	    August September October November December)[m - 1]
+    ca = ca + ' ' + y.to_s if not @opt_y
+    ca = ca.center(@mw)
+
+    ta.unshift(ca)
+  end
+
+  def group(xs, n)
+    (0..xs.size / n - 1).collect{|i| xs[i * n, n]}
+  end
+
+  def trans(xs)
+    (0..xs[0].size - 1).collect{|i| xs.collect{|x| x[i]}}
+  end
+
+  def stack(xs)
+    if xs.empty? then [] else xs[0] + stack(xs[1..-1]) end
+  end
+
+  def block(xs, n)
+    stack(group(xs, n).collect{|ys| trans(ys).collect{|zs| zs.join('  ')}})
+  end
+
+  def unlines(xs)
+    xs.collect{|x| x + "\n"}.join
+  end
+
+  def monthly(y, m)
+    unlines(pict(y, m))
+  end
+
+  def addmon(y, m, n)
+    y, m = (y * 12 + (m - 1) + n).divmod(12)
+    return y, m + 1
+  end
+
+  def yearly(y)
+    y.to_s.center(@tw) + "\n\n" +
+      unlines(block((0..11).collect{|n| pict(*addmon(y, 1, n))}, @mn)) + "\n"
+  end
+
+  def print(y, m)
+    set_params
+    if @opt_y then yearly(y) else monthly(y, m) end
+  end
 
-def group(xs, n)
-  (0..xs.size / n - 1).collect{|i| xs[i * n, n]}
 end
 
-def trans(xs)
-  (0..xs[0].size - 1).collect{|i| xs.collect{|x| x[i]}}
-end
+if __FILE__ == $0
 
-def unite(xs)
-  if xs.empty? then [] else xs[0] + unite(xs[1..-1]) end
-end
+  require 'getopts'
 
-def block(xs, n)
-  unite(group(xs, n).collect{|ys| trans(ys).collect{|zs| zs.join('  ')}})
-end
+  def usage
+    warn 'usage: cal [-c iso3166] [-jmty] [[month] year]'
+    exit 1
+  end
 
-def unlines(xs)
-  xs.collect{|x| x + "\n"}.join
-end
+  usage unless getopts('jmty', "c:#{Cal::DEFAULT_START}")
 
-usage unless getopts('jmty', "c:#{$cc}")
+  y, m = ARGV.values_at(1, 0).compact.collect{|x| x.to_i}
+  $OPT_y ||= (y and not m)
 
-y, m = ARGV.values_at(1, 0).compact.collect{|x| x.to_i}
-$OPT_y ||= (y and not m)
+  to = Date.today
+  y ||= to.year
+  m ||= to.mon
 
-to = Date.today
-y ||= to.year
-m ||= to.mon
+  usage unless m >= 1 and m <= 12
+  usage unless y >= -4712
+  usage if Cal::START[$OPT_c].nil?
 
-usage unless m >= 1 and m <= 12
-usage unless y >= -4712
-usage if (sg = $tab[$OPT_c]).nil?
+  cal = Cal.new
 
-$dw = if $OPT_j then 3 else 2 end
-$mw = ($dw + 1) * 7 - 1
-$mn = if $OPT_j then 2 else 3 end
-$tw = ($mw + 2) * $mn - 2
+  cal.opt_j($OPT_j)
+  cal.opt_m($OPT_m)
+  cal.opt_t($OPT_t)
+  cal.opt_y($OPT_y)
+  cal.opt_c($OPT_c)
 
-$k  = if $OPT_m then 1 else 0 end
-$da = if $OPT_j then :yday else :mday end
+  print cal.print(y, m)
 
-print(if not $OPT_y
-	unlines(pict(y, m, sg))
-      else
-	y.to_s.center($tw) + "\n\n" +
-	  unlines(block((1..12).collect{|m| pict(y, m, sg)}, $mn)) + "\n"
-      end)
+end