Add %G, %g, %V direcives to Time::Format

spec/std/time/format_spec.cr

@@ -99,9 +99,27 @@ describe Time::Format do
       t3.to_s("%u").to_s.should eq("7")
       t3.to_s("%w").to_s.should eq("0")
 
-      # TODO %G
-      # TODO %g
-      # TODO %V
+      Time.utc(1985, 4, 12).to_s("%G-W%V-%u").should eq "1985-W15-5"
+      Time.utc(2005, 1, 1).to_s("%G-W%V-%u").should eq "2004-W53-6"
+      Time.utc(2005, 1, 2).to_s("%G-W%V-%u").should eq "2004-W53-7"
+      Time.utc(2005, 12, 31).to_s("%G-W%V-%u").should eq "2005-W52-6"
+      Time.utc(2006, 1, 1).to_s("%G-W%V-%u").should eq "2005-W52-7"
+      Time.utc(2006, 1, 2).to_s("%G-W%V-%u").should eq "2006-W01-1"
+      Time.utc(2006, 12, 31).to_s("%G-W%V-%u").should eq "2006-W52-7"
+      Time.utc(2007, 1, 1).to_s("%G-W%V-%u").should eq "2007-W01-1"
+      Time.utc(2007, 12, 30).to_s("%G-W%V-%u").should eq "2007-W52-7"
+      Time.utc(2007, 12, 31).to_s("%G-W%V-%u").should eq "2008-W01-1"
+      Time.utc(2008, 1, 1).to_s("%G-W%V-%u").should eq "2008-W01-2"
+      Time.utc(2008, 12, 28).to_s("%G-W%V-%u").should eq "2008-W52-7"
+      Time.utc(2008, 12, 29).to_s("%G-W%V-%u").should eq "2009-W01-1"
+      Time.utc(2008, 12, 30).to_s("%G-W%V-%u").should eq "2009-W01-2"
+      Time.utc(2008, 12, 31).to_s("%G-W%V-%u").should eq "2009-W01-3"
+      Time.utc(2009, 1, 1).to_s("%G-W%V-%u").should eq "2009-W01-4"
+      Time.utc(2009, 12, 31).to_s("%G-W%V-%u").should eq "2009-W53-4"
+      Time.utc(2010, 1, 1).to_s("%G-W%V-%u").should eq "2009-W53-5"
+      Time.utc(2010, 1, 2).to_s("%G-W%V-%u").should eq "2009-W53-6"
+      Time.utc(2010, 1, 3).to_s("%G-W%V-%u").should eq "2009-W53-7"
+      Time.utc(1985, 4, 12).to_s("%g-W%V-%u").should eq "85-W15-5"
       # TODO %U
       # TODO %W
       # TODO %s
@@ -208,6 +226,27 @@ describe Time::Format do
     parse_time("今は Friday, October 31, 2014", "今は %A, %B %d, %Y").to_s.should eq("2014-10-31 00:00:00 UTC")
     parse_time("epoch: 1459864667", "epoch: %s").epoch.should eq(1459864667)
     parse_time("epoch: -1459864667", "epoch: %s").epoch.should eq(-1459864667)
+
+    parse_time("1985-W15-5", "%G-W%V-%u").should eq(Time.utc(1985, 4, 12))
+    parse_time("2004-W53-6", "%G-W%V-%u").should eq(Time.utc(2005, 1, 1))
+    parse_time("2004-W53-7", "%G-W%V-%u").should eq(Time.utc(2005, 1, 2))
+    parse_time("2005-W52-6", "%G-W%V-%u").should eq(Time.utc(2005, 12, 31))
+    parse_time("2005-W52-7", "%G-W%V-%u").should eq(Time.utc(2006, 1, 1))
+    parse_time("2006-W01-1", "%G-W%V-%u").should eq(Time.utc(2006, 1, 2))
+    parse_time("2006-W52-7", "%G-W%V-%u").should eq(Time.utc(2006, 12, 31))
+    parse_time("2007-W01-1", "%G-W%V-%u").should eq(Time.utc(2007, 1, 1))
+    parse_time("2007-W52-7", "%G-W%V-%u").should eq(Time.utc(2007, 12, 30))
+    parse_time("2008-W01-1", "%G-W%V-%u").should eq(Time.utc(2007, 12, 31))
+    parse_time("2008-W01-2", "%G-W%V-%u").should eq(Time.utc(2008, 1, 1))
+    parse_time("2008-W52-7", "%G-W%V-%u").should eq(Time.utc(2008, 12, 28))
+    parse_time("2009-W01-1", "%G-W%V-%u").should eq(Time.utc(2008, 12, 29))
+    parse_time("2009-W01-2", "%G-W%V-%u").should eq(Time.utc(2008, 12, 30))
+    parse_time("2009-W01-3", "%G-W%V-%u").should eq(Time.utc(2008, 12, 31))
+    parse_time("2009-W01-4", "%G-W%V-%u").should eq(Time.utc(2009, 1, 1))
+    parse_time("2009-W53-4", "%G-W%V-%u").should eq(Time.utc(2009, 12, 31))
+    parse_time("2009-W53-5", "%G-W%V-%u").should eq(Time.utc(2010, 1, 1))
+    parse_time("2009-W53-6", "%G-W%V-%u").should eq(Time.utc(2010, 1, 2))
+    parse_time("2009-W53-7", "%G-W%V-%u").should eq(Time.utc(2010, 1, 3))
   end
 
   it "parses timezone" do

src/time/format.cr

@@ -24,6 +24,8 @@ require "./format/parser"
 # * **%D**: date (04/05/16)
 # * **%e**: day of month, blank padded (" 1", " 2", ..., "10", "11", ...)
 # * **%F**: ISO 8601 date (2016-04-05)
+# * **%g**: week-based calendar year modulo 100 (00..99)
+# * **%G**: week-based calendar year (0001..9999)
 # * **%h**: (same as %b) short month name (Jan, Feb, Mar, ...)
 # * **%H**: hour of the day, 24-hour clock, zero padded (00, 01, ..., 24)
 # * **%I**: hour of the day, 12-hour clock, zero padded (00, 01, ..., 12)
@@ -47,6 +49,7 @@ require "./format/parser"
 # * **%S**: seconds, zero padded (00, 01, ..., 59)
 # * **%T**: 24-hour time (13:04:05)
 # * **%u**: day of week (Monday is 1, 1..7)
+# * **%V**: ISO calendar week number of the week-based year (01..53)
 # * **%w**: day of week (Sunday is 0, 0..6)
 # * **%x**: (same as %D) date (04/05/16)
 # * **%X**: (same as %T) 24-hour time (13:04:05)

src/time/format/formatter.cr

@@ -27,6 +27,14 @@ struct Time::Format
       year
     end
 
+    def calendar_week_year
+      pad4(time.calendar_week[0], '0')
+    end
+
+    def calendar_week_year_modulo100
+      pad2(time.calendar_week[0] % 100, '0')
+    end
+
     def month
       io << time.month
     end
@@ -55,6 +63,10 @@ struct Time::Format
       io << get_short_month_name.upcase
     end
 
+    def calendar_week_week
+      pad2(time.calendar_week[1], '0')
+    end
+
     def day_of_month
       io << time.day
     end

src/time/format/parser.cr

@@ -19,6 +19,9 @@ struct Time::Format
 
     @epoch : Int64?
     @location : Location?
+    @calendar_week_week : Int32?
+    @calendar_week_year : Int32?
+    @day_of_week : Time::DayOfWeek?
 
     def initialize(string)
       @reader = Char::Reader.new(string)
@@ -45,7 +48,13 @@ struct Time::Format
         raise "Time format did not include time zone and no default location provided", pos: false
       end
 
-      time = Time.new @year, @month, @day, @hour, @minute, @second, nanosecond: @nanosecond, location: location
+      if (calendar_week_week = @calendar_week_week) && (calendar_week_year = @calendar_week_year) && (day_of_week = @day_of_week)
+        # If all components of a week date are available, they are used to create a Time instance
+        time = Time.week_date calendar_week_year, calendar_week_week, day_of_week, @hour, @minute, @second, nanosecond: @nanosecond, location: location
+      else
+        time = Time.new @year, @month, @day, @hour, @minute, @second, nanosecond: @nanosecond, location: location
+      end
+
       time = time.add_span 0, @nanosecond_offset
 
       time
@@ -81,6 +90,14 @@ struct Time::Format
               end
     end
 
+    def calendar_week_year
+      @calendar_week_year = consume_number(4)
+    end
+
+    def calendar_week_year_modulo100
+      @calendar_week_year = consume_number(2)
+    end
+
     def month
       @month = consume_number(2)
     end
@@ -131,6 +148,10 @@ struct Time::Format
       month_name
     end
 
+    def calendar_week_week
+      @calendar_week_week = consume_number(2)
+    end
+
     def day_of_month
       @day = consume_number(2)
     end
@@ -261,11 +282,11 @@ struct Time::Format
     end
 
     def day_of_week_monday_1_7
-      consume_number(1)
+      @day_of_week = Time::DayOfWeek.from_value(consume_number(1))
     end
 
     def day_of_week_sunday_0_6
-      consume_number(1)
+      @day_of_week = Time::DayOfWeek.from_value(consume_number(1))
     end
 
     def epoch

src/time/format/pattern.cr

@@ -34,6 +34,10 @@ struct Time::Format
           day_of_month_blank_padded
         when 'F'
           year_month_day
+        when 'g'
+          calendar_week_year_modulo100
+        when 'G'
+          calendar_week_year
         when 'H'
           hour_24_zero_padded
         when 'I'
@@ -68,6 +72,8 @@ struct Time::Format
           twenty_four_hour_time_with_seconds
         when 'u'
           day_of_week_monday_1_7
+        when 'V'
+          calendar_week_week
         when 'w'
           day_of_week_sunday_0_6
         when 'y'