Add reverse to count

lib/youplot/backends/processing.rb

@@ -6,22 +6,30 @@ module YouPlot
     module Processing
       module_function
 
-      def count_values(arr, tally: true)
+      def count_values(arr, tally: true, reverse: false)
         # tally was added in Ruby 2.7
-        if tally && Enumerable.method_defined?(:tally)
-          arr.tally
-        else
-          # value_counts Enumerable::Statistics
-          arr.value_counts(dropna: false)
-        end
-          .sort do |a, b|
-            # compare values
-            r = b[1] <=> a[1]
-            # If the values are the same, compare by name
-            r = a[0] <=> b[0] if r == 0
-            r
+        result = \
+          if tally && Enumerable.method_defined?(:tally)
+            arr.tally
+          else
+            # value_counts Enumerable::Statistics
+            arr.value_counts(dropna: false)
           end
-          .transpose
+
+        # sorting
+        result = result.sort do |a, b|
+          # compare values
+          r = b[1] <=> a[1]
+          # If the values are the same, compare by name
+          r = a[0] <=> b[0] if r == 0
+          r
+        end
+
+        # --reverse option
+        result.reverse! if reverse
+
+        # prepare for barplot
+        result.transpose
       end
     end
   end

lib/youplot/backends/unicode_plot.rb

@@ -14,12 +14,12 @@ module YouPlot
 
       module_function
 
-      def barplot(data, params, fmt = nil, count: false)
+      def barplot(data, params, fmt = nil, count: false, reverse: false)
         headers = data.headers
         series = data.series
         # `uplot count`
         if count
-          series = Processing.count_values(series[0])
+          series = Processing.count_values(series[0], reverse: reverse)
           params.title = headers[0] if headers
         end
         if series.size == 1

lib/youplot/command.rb

@@ -146,7 +146,7 @@ module YouPlot
       when :bar, :barplot
         @backend.barplot(data, params, options[:fmt])
       when :count, :c
-        @backend.barplot(data, params, count: true)
+        @backend.barplot(data, params, count: true, reverse: options[:reverse])
       when :hist, :histogram
         @backend.histogram(data, params)
       when :line, :lineplot

lib/youplot/options.rb

@@ -11,7 +11,8 @@ module YouPlot
     :fmt,
     :progressive,
     :encoding,
-    :color_names,
+    :reverse,      # count
+    :color_names,  # color
     :debug,
     keyword_init: true
   )

lib/youplot/parser.rb

@@ -23,6 +23,7 @@ module YouPlot
         fmt: 'xyy',
         progressive: false,
         encoding: nil,
+        reverse: false,
         color_names: false,
         debug: false
       )
@@ -163,7 +164,8 @@ module YouPlot
     end
 
     def sub_parser_add_canvas
-      sub_parser.on_head('--canvas STR', String, 'type of canvas') do |v|
+      canvas_types = UnicodePlot::Canvas::CANVAS_CLASS_MAP.keys.join(", ")
+      sub_parser.on_head('--canvas STR', String, "type of canvas", "(#{canvas_types})") do |v|
         params.canvas = v.to_sym
       end
     end
@@ -226,6 +228,9 @@ module YouPlot
         sub_parser_add_xscale
 
       when :count, :c
+        sub_parser.on_head('-r', '--reverse', TrueClass, 'reverse the result of comparisons') do |v|
+          options.reverse = v
+        end
         sub_parser_add_symbol
         sub_parser_add_xscale
 
@@ -270,7 +275,7 @@ module YouPlot
         sub_parser_add_xlim
 
       when :colors, :color, :colours, :colour
-        sub_parser.on_head('-n', '--names', 'show color names only', TrueClass) do |v|
+        sub_parser.on_head('-n', '--names', TrueClass, 'show color names only') do |v|
           options[:color_names] = v
         end