Support number format option. (sugi#11)

Fix standard Date#strftime compatibility

lib/wareki/date.rb

@@ -159,18 +159,29 @@ def to_time
     end
 
     def strftime(format_str = '%JF')
-      ret = format_str.to_str.gsub(/%J(-|[_0]?[0-9]+|)([fFyYegGoOiImMsSlLdD][kK]?)/) { format($2, $1) || $& }
+      ret = format_str.to_str.gsub(/%J(-|[_0]{0,2}[0-9]*|)([fFyYegGoOiImMsSlLdD][kK]?)/) { format($2, $1) || $& }
       ret.index('%') or return ret
       d = to_date
       d.respond_to?(:_wareki_strftime_orig) ? d._wareki_strftime_orig(ret) : d.strftime(ret)
     end
 
-    def format(key, opt = "")
-      sprintf_format = (opt.empty? ? "%02d" : "%#{opt.sub('_', '')}d")
+    def _number_format(opt)
+      case opt
+      when ''    then '%02d'
+      when '-'   then '%d'
+      when '0'   then '%02d'
+      when '_0'  then '%02d'
+      when /_\Z/ then '%2d'
+      when /0?_/ then "\%#{opt.sub(/0?_/, '')}d"
+      when /_?0/ then "\%#{opt.sub(/_?0/, '0')}d"
+      else "\%0#{opt}d"
+      end
+    end
 
+    def format(key, opt = '')
       case key.to_sym
       when :e  then era_name
-      when :g  then era_name.to_s == '' ? '' : (sprintf_format % era_year)
+      when :g  then era_name.to_s == '' ? '' : Kernel.format(_number_format(opt), era_year)
       when :G  then era_name.to_s == '' ? '' : Utils.i2z(era_year)
       when :Gk then era_name.to_s == '' ? '' : YaKansuji.to_kan(era_year, :simple)
       when :GK
@@ -187,14 +198,14 @@ def format(key, opt = "")
       when :i  then imperial_year
       when :I  then Utils.i2z(imperial_year)
       when :Ik then YaKansuji.to_kan(imperial_year, :simple)
-      when :s  then (sprintf_format % month)
+      when :s  then Kernel.format(_number_format(opt), month)
       when :S  then Utils.i2z(month)
       when :Sk then YaKansuji.to_kan(month, :simple)
       when :SK then Utils.alt_month_name(month)
       when :l  then leap_month? ? "'" : ''
       when :L  then leap_month? ? '’' : ''
       when :Lk then leap_month? ? '閏' : ''
-      when :d  then (sprintf_format % day)
+      when :d  then Kernel.format(_number_format(opt), day)
       when :D  then Utils.i2z(day)
       when :Dk then YaKansuji.to_kan(day, :simple)
       when :DK

spec/date_spec.rb

@@ -190,15 +190,18 @@ def self.days(v); new; end
     expect(d.strftime("%Jm %JM %JMk")).to eq "05' 閏５ 閏五"
     expect(d.strftime("%Jy %JY %JYk")).to eq "天和03 天和３ 天和三"
 
-    expect(d.strftime("1桁: %J01f")).to eq "1桁: 天和3年5'月4日"
-    expect(d.strftime("1桁: %J01y %J01m %J01d")).to eq "1桁: 天和3 5' 4"
-    expect(d.strftime("1桁: %J01g %J01s")).to eq "1桁: 3 5"
+    expect(d.strftime("1桁: %J1f")).to eq "1桁: 天和3年5'月4日"
+    expect(d.strftime("1桁: %J1y %J1m %J1d")).to eq "1桁: 天和3 5' 4"
+    expect(d.strftime("1桁: %J1g %J1s")).to eq "1桁: 3 5"
     expect(d.strftime("空白2桁: %J_2f")).to eq "空白2桁: 天和 3年 5'月 4日"
     expect(d.strftime("空白2桁: %J_2y %J_2m %J_2d")).to eq "空白2桁: 天和 3  5'  4"
     expect(d.strftime("空白2桁: %J_2g %J_2s")).to eq "空白2桁:  3  5"
     expect(d.strftime("0埋3桁: %J03f")).to eq "0埋3桁: 天和003年005'月004日"
     expect(d.strftime("0埋3桁: %J03y %J03m %J03d")).to eq "0埋3桁: 天和003 005' 004"
     expect(d.strftime("0埋3桁: %J03g %J03s")).to eq "0埋3桁: 003 005"
+    expect(d.strftime("0埋4桁: %J4f")).to eq "0埋4桁: 天和0003年0005'月0004日"
+    expect(d.strftime("0埋4桁: %J4y %J4m %J4d")).to eq "0埋4桁: 天和0003 0005' 0004"
+    expect(d.strftime("0埋4桁: %J4g %J4s")).to eq "0埋4桁: 0003 0005"
 
     expect(d.strftime("皇紀で%Ji年%Jm月%Jd日")).to eq "皇紀で2343年05'月04日"
     expect(d.strftime("%JYk年　%JSK")).to eq "天和三年　皐月"
@@ -212,6 +215,26 @@ def self.days(v); new; end
     expect(Wareki::Date.new("寿永", 1, 1, 1).strftime("%JYK年%JM%JL月%JDK日")).to eq "寿永元年１月元日"
   end
 
+  it "can be formatted having compatibility with standard Date#strftime" do
+    wareki_date = Wareki::Date.new("令和", 1, 5, 4)
+    date = ::Date.new(2019, 5, 4)
+
+    expect(wareki_date.strftime("%Jm %Jd")).to eq date.strftime("%m %d")
+    expect(wareki_date.strftime("%J-m %J-d")).to eq date.strftime("%-m %-d")
+
+    expect(wareki_date.strftime("%J_m %J_d")).to eq date.strftime("%_m %_d")
+    expect(wareki_date.strftime("%J_2m %J_2d")).to eq date.strftime("%_2m %_2d")
+    expect(wareki_date.strftime("%J03m %J03d")).to eq date.strftime("%03m %03d")
+    expect(wareki_date.strftime("%J4m %J4d")).to eq date.strftime("%4m %4d")
+
+    expect(wareki_date.strftime("%J0_5m %J0_5d")).to eq date.strftime("%0_5m %0_5d")
+    expect(wareki_date.strftime("%J_06m %J_06d")).to eq date.strftime("%_06m %_06d")
+
+    expect(wareki_date.strftime("%J0m %J0d")).to eq date.strftime("%0m %0d")
+    expect(wareki_date.strftime("%J0_m %J0_d")).to eq date.strftime("%0_m %0_d")
+    expect(wareki_date.strftime("%J_0m %J_0d")).to eq date.strftime("%_0m %_0d")
+  end
+
   it "can handle last days of era" do
     expect(Date.parse("1989/1/7").strftime('%JF')).to eq "昭和六十四年一月七日"
     expect(Date.parse("1912/7/29").strftime('%JF')).to eq "明治四十五年七月二十九日"