Adds number_to_human and several improvements in NumberHelper. [#4239 state:resolved]

Signed-off-by: José Valim <jose.valim@gmail.com>

1 files changed, 229 insertions, 92 deletions

diff --git a/actionpack/lib/action_view/helpers/number_helper.rb b/actionpack/lib/action_view/helpers/number_helper.rb
index 46e41bc406..00c54f7644 100644
--- a/actionpack/lib/action_view/helpers/number_helper.rb
+++ b/actionpack/lib/action_view/helpers/number_helper.rb
@@ -5,7 +5,10 @@ module ActionView
   module Helpers #:nodoc:
     # Provides methods for converting numbers into formatted strings.
     # Methods are provided for phone numbers, currency, percentage,
-    # precision, positional notation, and file size.
+    # precision, positional notation, file size and pretty printing.
+    #
+    # Most methods expect a +number+ argument, and will return it
+    # unchanged if can't be converted into a valid number.
     module NumberHelper
       # Formats a +number+ into a US phone number (e.g., (555) 123-9876). You can customize the format
       # in the +options+ hash.
@@ -74,21 +77,16 @@ module ActionView
       def number_to_currency(number, options = {})
         options.symbolize_keys!
 
-        defaults  = I18n.translate(:'number.format', :locale => options[:locale], :raise => true) rescue {}
-        currency  = I18n.translate(:'number.currency.format', :locale => options[:locale], :raise => true) rescue {}
+        defaults  = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
+        currency  = I18n.translate(:'number.currency.format', :locale => options[:locale], :default => {})
         defaults  = defaults.merge(currency)
 
-        precision = options[:precision] || defaults[:precision]
-        unit      = options[:unit]      || defaults[:unit]
-        separator = options[:separator] || defaults[:separator]
-        delimiter = options[:delimiter] || defaults[:delimiter]
-        format    = options[:format]    || defaults[:format]
-        separator = '' if precision == 0
+        options = options.reverse_merge(defaults)
 
-        value = number_with_precision(number,
-          :precision => precision,
-          :delimiter => delimiter,
-          :separator => separator)
+        unit      = options.delete(:unit)
+        format    = options.delete(:format)
+
+        value = number_with_precision(number, options)
 
         if value
           format.gsub(/%n/, value).gsub(/%u/, unit).html_safe
@@ -101,9 +99,11 @@ module ActionView
       # format in the +options+ hash.
       #
       # ==== Options
-      # * <tt>:precision</tt>  - Sets the level of precision (defaults to 3).
-      # * <tt>:separator</tt>  - Sets the separator between the units (defaults to ".").
+      # * <tt>:precision</tt>  - Sets the precision of the number (defaults to 3).
+      # * <tt>:significant</tt>  - If +true+, precision will be the # of significant_digits. If +false+, the # of fractional digits (defaults to +false+)
+      # * <tt>:separator</tt>  - Sets the separator between the fractional and integer digits (defaults to ".").
       # * <tt>:delimiter</tt>  - Sets the thousands delimiter (defaults to "").
+      # * <tt>:strip_unsignificant_zeros</tt>  - If +true+ removes unsignificant zeros after the decimal separator (defaults to +false+)
       #
       # ==== Examples
       #  number_to_percentage(100)                                        # => 100.000%
@@ -113,18 +113,13 @@ module ActionView
       def number_to_percentage(number, options = {})
         options.symbolize_keys!
 
-        defaults   = I18n.translate(:'number.format', :locale => options[:locale], :raise => true) rescue {}
-        percentage = I18n.translate(:'number.percentage.format', :locale => options[:locale], :raise => true) rescue {}
+        defaults   = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
+        percentage = I18n.translate(:'number.percentage.format', :locale => options[:locale], :default => {})
         defaults  = defaults.merge(percentage)
 
-        precision = options[:precision] || defaults[:precision]
-        separator = options[:separator] || defaults[:separator]
-        delimiter = options[:delimiter] || defaults[:delimiter]
+        options = options.reverse_merge(defaults)
 
-        value = number_with_precision(number,
-          :precision => precision,
-          :separator => separator,
-          :delimiter => delimiter)
+        value = number_with_precision(number, options)
         value ? value + "%" : number
       end
 
@@ -133,7 +128,7 @@ module ActionView
       #
       # ==== Options
       # * <tt>:delimiter</tt>  - Sets the thousands delimiter (defaults to ",").
-      # * <tt>:separator</tt>  - Sets the separator between the units (defaults to ".").
+      # * <tt>:separator</tt>  - Sets the separator between the fractional and integer digits (defaults to ".").
       #
       # ==== Examples
       #  number_with_delimiter(12345678)                        # => 12,345,678
@@ -146,139 +141,163 @@ module ActionView
       # You can still use <tt>number_with_delimiter</tt> with the old API that accepts the
       # +delimiter+ as its optional second and the +separator+ as its
       # optional third parameter:
-      #  number_with_delimiter(12345678, " ")                     # => 12 345.678
+      #  number_with_delimiter(12345678, " ")                     # => 12 345 678
       #  number_with_delimiter(12345678.05, ".", ",")             # => 12.345.678,05
       def number_with_delimiter(number, *args)
         options = args.extract_options!
         options.symbolize_keys!
 
-        defaults = I18n.translate(:'number.format', :locale => options[:locale], :raise => true) rescue {}
+        defaults = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
 
         unless args.empty?
           ActiveSupport::Deprecation.warn('number_with_delimiter takes an option hash ' +
             'instead of separate delimiter and precision arguments.', caller)
-          delimiter = args[0] || defaults[:delimiter]
-          separator = args[1] || defaults[:separator]
+          options[:delimiter] ||= args[0] if args[0]
+          options[:separator] ||= args[1] if args[1]
         end
 
-        delimiter ||= (options[:delimiter] || defaults[:delimiter])
-        separator ||= (options[:separator] || defaults[:separator])
+        options = options.reverse_merge(defaults)
 
         parts = number.to_s.split('.')
         if parts[0]
-          parts[0].gsub!(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1#{delimiter}")
-          parts.join(separator)
+          parts[0].gsub!(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1#{options[:delimiter]}")
+          parts.join(options[:separator])
         else
           number
         end
+
       end
 
-      # Formats a +number+ with the specified level of <tt>:precision</tt> (e.g., 112.32 has a precision of 2).
+      # Formats a +number+ with the specified level of <tt>:precision</tt> (e.g., 112.32 has a precision
+      # of 2 if +:significant+ is +false+, and 5 if +:significant+ is +true+).
       # You can customize the format in the +options+ hash.
       #
       # ==== Options
-      # * <tt>:precision</tt>  - Sets the level of precision (defaults to 3).
-      # * <tt>:separator</tt>  - Sets the separator between the units (defaults to ".").
+      # * <tt>:precision</tt>  - Sets the precision of the number (defaults to 3).
+      # * <tt>:significant</tt>  - If +true+, precision will be the # of significant_digits. If +false+, the # of fractional digits (defaults to +false+)
+      # * <tt>:separator</tt>  - Sets the separator between the fractional and integer digits (defaults to ".").
       # * <tt>:delimiter</tt>  - Sets the thousands delimiter (defaults to "").
+      # * <tt>:strip_unsignificant_zeros</tt>  - If +true+ removes unsignificant zeros after the decimal separator (defaults to +false+)
       #
       # ==== Examples
-      #  number_with_precision(111.2345)                    # => 111.235
-      #  number_with_precision(111.2345, :precision => 2)   # => 111.23
-      #  number_with_precision(13, :precision => 5)         # => 13.00000
-      #  number_with_precision(389.32314, :precision => 0)  # => 389
+      #  number_with_precision(111.2345)                                            # => 111.235
+      #  number_with_precision(111.2345, :precision => 2)                           # => 111.23
+      #  number_with_precision(13, :precision => 5)                                 # => 13.00000
+      #  number_with_precision(389.32314, :precision => 0)                          # => 389
+      #  number_with_precision(111.2345, :significant => true)                      # => 111
+      #  number_with_precision(111.2345, :precision => 1, :significant => true)     # => 100
+      #  number_with_precision(13, :precision => 5, :significant => true)           # => 13.000
+      #  number_with_precision(13, :precision => 5, :significant => true, strip_unsignificant_zeros => true)
+      #  # => 13
+      #  number_with_precision(389.32314, :precision => 4, :significant => true)    # => 389.3
       #  number_with_precision(1111.2345, :precision => 2, :separator => ',', :delimiter => '.')
       #  # => 1.111,23
       #
       # You can still use <tt>number_with_precision</tt> with the old API that accepts the
       # +precision+ as its optional second parameter:
-      #   number_with_precision(number_with_precision(111.2345, 2)   # => 111.23
+      #   number_with_precision(111.2345, 2)   # => 111.23
       def number_with_precision(number, *args)
+        number = begin
+          Float(number)
+        rescue ArgumentError, TypeError
+          return number
+        end
+
         options = args.extract_options!
         options.symbolize_keys!
 
-        defaults           = I18n.translate(:'number.format', :locale => options[:locale], :raise => true) rescue {}
-        precision_defaults = I18n.translate(:'number.precision.format', :locale => options[:locale],
-                                                                        :raise => true) rescue {}
+        defaults           = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
+        precision_defaults = I18n.translate(:'number.precision.format', :locale => options[:locale], :default => {})
         defaults           = defaults.merge(precision_defaults)
 
+        #Backwards compatibility
         unless args.empty?
           ActiveSupport::Deprecation.warn('number_with_precision takes an option hash ' +
             'instead of a separate precision argument.', caller)
-          precision = args[0] || defaults[:precision]
+          options[:precision] ||= args[0] if args[0]
         end
 
-        precision ||= (options[:precision] || defaults[:precision])
-        separator ||= (options[:separator] || defaults[:separator])
-        delimiter ||= (options[:delimiter] || defaults[:delimiter])
+        options = options.reverse_merge(defaults)  # Allow the user to unset default values: Eg.: :significant => false
+        precision = options.delete :precision
+        significant = options.delete :significant
+        strip_unsignificant_zeros = options.delete :strip_unsignificant_zeros
 
-        begin
-          value = Float(number)
-        rescue ArgumentError, TypeError
-          value = nil
+        if significant and precision > 0
+          digits = (Math.log10(number) + 1).floor
+          rounded_number = BigDecimal.new((number / 10 ** (digits - precision)).to_s).round.to_f * 10 ** (digits - precision)
+          precision = precision - digits
+          precision = precision > 0 ? precision : 0  #don't let it be negative
+        else
+          rounded_number = BigDecimal.new((number * (10 ** precision)).to_s).round.to_f / 10 ** precision
         end
-
-        if value
-          rounded_number = BigDecimal.new((Float(number) * (10 ** precision)).to_s).round.to_f / 10 ** precision
-          number_with_delimiter("%01.#{precision}f" % rounded_number,
-            :separator => separator,
-            :delimiter => delimiter)
+        formatted_number = number_with_delimiter("%01.#{precision}f" % rounded_number, options)
+        if strip_unsignificant_zeros
+          escaped_separator = Regexp.escape(options[:separator])
+          formatted_number.sub(/(#{escaped_separator})(\d*[1-9])?0+\z/, '\1\2').sub(/#{escaped_separator}\z/, '')
         else
-          number
+          formatted_number
         end
+
       end
 
       STORAGE_UNITS = [:byte, :kb, :mb, :gb, :tb].freeze
 
-      # Formats the bytes in +size+ into a more understandable representation
+      # Formats the bytes in +number+ into a more understandable representation
       # (e.g., giving it 1500 yields 1.5 KB). This method is useful for
-      # reporting file sizes to users. This method returns nil if
-      # +size+ cannot be converted into a number. You can customize the
+      # reporting file sizes to users. You can customize the
       # format in the +options+ hash.
       #
+      # See <tt>number_to_human</tt> if you want to pretty-print a generic number.
+      #
       # ==== Options
-      # * <tt>:precision</tt>  - Sets the level of precision (defaults to 1).
-      # * <tt>:separator</tt>  - Sets the separator between the units (defaults to ".").
+      # * <tt>:precision</tt>  - Sets the precision of the number (defaults to 3).
+      # * <tt>:significant</tt>  - If +true+, precision will be the # of significant_digits. If +false+, the # of fractional digits (defaults to +true+)
+      # * <tt>:separator</tt>  - Sets the separator between the fractional and integer digits (defaults to ".").
       # * <tt>:delimiter</tt>  - Sets the thousands delimiter (defaults to "").
-      #
+      # * <tt>:strip_unsignificant_zeros</tt>  - If +true+ removes unsignificant zeros after the decimal separator (defaults to +true+)
       # ==== Examples
       #  number_to_human_size(123)                                          # => 123 Bytes
-      #  number_to_human_size(1234)                                         # => 1.2 KB
+      #  number_to_human_size(1234)                                         # => 1.21 KB
       #  number_to_human_size(12345)                                        # => 12.1 KB
-      #  number_to_human_size(1234567)                                      # => 1.2 MB
-      #  number_to_human_size(1234567890)                                   # => 1.1 GB
-      #  number_to_human_size(1234567890123)                                # => 1.1 TB
-      #  number_to_human_size(1234567, :precision => 2)                     # => 1.18 MB
-      #  number_to_human_size(483989, :precision => 0)                      # => 473 KB
-      #  number_to_human_size(1234567, :precision => 2, :separator => ',')  # => 1,18 MB
+      #  number_to_human_size(1234567)                                      # => 1.18 MB
+      #  number_to_human_size(1234567890)                                   # => 1.15 GB
+      #  number_to_human_size(1234567890123)                                # => 1.12 TB
+      #  number_to_human_size(1234567, :precision => 2)                     # => 1.2 MB
+      #  number_to_human_size(483989, :precision => 2)                      # => 470 KB
+      #  number_to_human_size(1234567, :precision => 2, :separator => ',')  # => 1,2 MB
       #
-      # Zeros after the decimal point are always stripped out, regardless of the
-      # specified precision:
-      #  helper.number_to_human_size(1234567890123, :precision => 5)        # => "1.12283 TB"
-      #  helper.number_to_human_size(524288000, :precision=>5)              # => "500 MB"
+      # Unsignificant zeros after the fractional separator are stripped out by default (set
+      # <tt>:strip_unsignificant_zeros</tt> to +false+ to change that):
+      #  number_to_human_size(1234567890123, :precision => 5)        # => "1.1229 TB"
+      #  number_to_human_size(524288000, :precision=>5)              # => "500 MB"
       #
       # You can still use <tt>number_to_human_size</tt> with the old API that accepts the
       # +precision+ as its optional second parameter:
-      #  number_to_human_size(1234567, 2)    # => 1.18 MB
-      #  number_to_human_size(483989, 0)     # => 473 KB
+      #  number_to_human_size(1234567, 1)    # => 1 MB
+      #  number_to_human_size(483989, 2)     # => 470 KB
       def number_to_human_size(number, *args)
-        return nil if number.nil?
+        number = begin
+          Float(number)
+        rescue ArgumentError, TypeError
+          return number
+        end
 
         options = args.extract_options!
         options.symbolize_keys!
 
-        defaults = I18n.translate(:'number.format', :locale => options[:locale], :raise => true) rescue {}
-        human    = I18n.translate(:'number.human.format', :locale => options[:locale], :raise => true) rescue {}
+        defaults = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
+        human    = I18n.translate(:'number.human.format', :locale => options[:locale], :default => {})
         defaults = defaults.merge(human)
 
         unless args.empty?
           ActiveSupport::Deprecation.warn('number_to_human_size takes an option hash ' +
             'instead of a separate precision argument.', caller)
-          precision = args[0] || defaults[:precision]
+          options[:precision] ||= args[0] if args[0]
         end
 
-        precision ||= (options[:precision] || defaults[:precision])
-        separator ||= (options[:separator] || defaults[:separator])
-        delimiter ||= (options[:delimiter] || defaults[:delimiter])
+        options = options.reverse_merge(defaults)
+        #for backwards compatibility with those that didn't add strip_unsignificant_zeros to their locale files
+        options[:strip_unsignificant_zeros] = true if not options.key?(:strip_unsignificant_zeros)
 
         storage_units_format = I18n.translate(:'number.human.storage_units.format', :locale => options[:locale], :raise => true)
 
@@ -287,7 +306,6 @@ module ActionView
           storage_units_format.gsub(/%n/, number.to_i.to_s).gsub(/%u/, unit)
         else
           max_exp  = STORAGE_UNITS.size - 1
-          number   = Float(number)
           exponent = (Math.log(number) / Math.log(1024)).to_i # Convert to base 1024
           exponent = max_exp if exponent > max_exp # we need this to avoid overflow for the highest unit
           number  /= 1024 ** exponent
@@ -295,15 +313,134 @@ module ActionView
           unit_key = STORAGE_UNITS[exponent]
           unit = I18n.translate(:"number.human.storage_units.units.#{unit_key}", :locale => options[:locale], :count => number, :raise => true)
 
-          escaped_separator = Regexp.escape(separator)
-          formatted_number = number_with_precision(number,
-            :precision => precision,
-            :separator => separator,
-            :delimiter => delimiter
-          ).sub(/(#{escaped_separator})(\d*[1-9])?0+\z/, '\1\2').sub(/#{escaped_separator}\z/, '')
+          formatted_number = number_with_precision(number, options)
           storage_units_format.gsub(/%n/, formatted_number).gsub(/%u/, unit)
         end
       end
+
+      DECIMAL_UNITS = {0 => :unit, 1 => :ten, 2 => :hundred, 3 => :thousand, 6 => :million, 9 => :billion, 12 => :trillion, 15 => :quadrillion,
+        -1 => :deci, -2 => :centi, -3 => :mili, -6 => :micro, -9 => :nano, -12 => :pico, -15 => :femto}.freeze
+
+      # Pretty prints (formats and approximates) a number in a way it is more readable by humans
+      # (eg.: 1200000000 becomes "1.2 Billion"). This is useful for numbers that
+      # can get very large (and too hard to read).
+      #
+      # See <tt>number_to_human_size</tt> if you want to print a file size.
+      #
+      # You can also define you own unit-quantifier names if you want to use other decimal units
+      # (eg.: 1500 becomes "1.5 kilometers", 0.150 becomes "150 mililiters", etc). You may define
+      # a wide range of unit quantifiers, even fractional ones (centi, deci, mili, etc).
+      #
+      # ==== Options
+      # * <tt>:precision</tt>  - Sets the precision of the number (defaults to 3).
+      # * <tt>:significant</tt>  - If +true+, precision will be the # of significant_digits. If +false+, the # of fractional digits (defaults to +true+)
+      # * <tt>:separator</tt>  - Sets the separator between the fractional and integer digits (defaults to ".").
+      # * <tt>:delimiter</tt>  - Sets the thousands delimiter (defaults to "").
+      # * <tt>:strip_unsignificant_zeros</tt>  - If +true+ removes unsignificant zeros after the decimal separator (defaults to +true+)
+      # * <tt>:units</tt> - A Hash of unit quantifier names. Or a string containing an i18n scope where to find this hash. It might have the following keys:
+      #   * *integers*: <tt>:unit</tt>, <tt>:ten</tt>, <tt>:hundred</tt>, <tt>:thousand</tt>,  <tt>:million</tt>,  <tt>:billion</tt>, <tt>:trillion</tt>, <tt>:quadrillion</tt>
+      #   * *fractionals*: <tt>:deci</tt>, <tt>:centi</tt>, <tt>:mili</tt>, <tt>:micro</tt>, <tt>:nano</tt>, <tt>:pico</tt>, <tt>:femto</tt>
+      # * <tt>:format</tt> - Sets the format of the output string (defaults to "%n %u"). The field types are:
+      #
+      #     %u  The quantifier (ex.: 'thousand')
+      #     %n  The number
+      #
+      # ==== Examples
+      #  number_to_human(123)                                          # => "123"
+      #  number_to_human(1234)                                         # => "1.23 Thousand"
+      #  number_to_human(12345)                                        # => "12.3 Thousand"
+      #  number_to_human(1234567)                                      # => "1.23 Million"
+      #  number_to_human(1234567890)                                   # => "1.23 Billion"
+      #  number_to_human(1234567890123)                                # => "1.23 Trillion"
+      #  number_to_human(1234567890123456)                             # => "1.23 Quadrillion"
+      #  number_to_human(1234567890123456789)                          # => "1230 Quadrillion"
+      #  number_to_human(489939, :precision => 2)                      # => "490 Thousand"
+      #  number_to_human(489939, :precision => 4)                      # => "489.9 Thousand"
+      #  number_to_human(1234567, :precision => 4,
+      #                           :significant => false)               # => "1.2346 Million"
+      #  number_to_human(1234567, :precision => 1,
+      #                           :separator => ',',
+      #                           :significant => false)               # => "1,2 Million"
+      #
+      # Unsignificant zeros after the decimal separator are stripped out by default (set
+      # <tt>:strip_unsignificant_zeros</tt> to +false+ to change that):
+      #  number_to_human(12345012345, :significant_digits => 6)       # => "12.345 Billion"
+      #  number_to_human(500000000, :precision=>5)                    # => "500 Million"
+      #
+      # ==== Custom Unit Quantifiers
+      #
+      # You can also use your own custom unit quantifiers:
+      #  number_to_human(500000, :units => {:unit => "ml", :thousand => "lt"})  # => "500 lt"
+      #
+      # If in your I18n locale you have:
+      #   distance:
+      #     centi:
+      #       one: "centimeter"
+      #       other: "centimeters"
+      #     unit:
+      #       one: "meter"
+      #       other: "meters"
+      #     thousand:
+      #       one: "kilometer"
+      #       other: "kilometers"
+      #     billion: "gazilion-distance"
+      #
+      # Then you could do:
+      #
+      #  number_to_human(543934, :units => :distance)                              # => "544 kilometers"
+      #  number_to_human(54393498, :units => :distance)                            # => "54400 kilometers"
+      #  number_to_human(54393498000, :units => :distance)                         # => "54.4 gazilion-distance"
+      #  number_to_human(343, :units => :distance, :precision => 1)                # => "300 meters"
+      #  number_to_human(1, :units => :distance)                                   # => "1 meter"
+      #  number_to_human(0.34, :units => :distance)                                # => "34 centimeters"
+      #
+      def number_to_human(number, options = {})
+        number = begin
+          Float(number)
+        rescue ArgumentError, TypeError
+          return number
+        end
+
+        options.symbolize_keys!
+
+        defaults = I18n.translate(:'number.format', :locale => options[:locale], :default => {})
+        human    = I18n.translate(:'number.human.format', :locale => options[:locale], :default => {})
+        defaults = defaults.merge(human)
+
+        options = options.reverse_merge(defaults)
+        #for backwards compatibility with those that didn't add strip_unsignificant_zeros to their locale files
+        options[:strip_unsignificant_zeros] = true if not options.key?(:strip_unsignificant_zeros)
+
+        units = options.delete :units
+        unit_exponents = case units
+        when Hash
+          units
+        when String, Symbol
+          I18n.translate(:"#{units}", :locale => options[:locale], :raise => true)
+        when nil
+          I18n.translate(:"number.human.decimal_units.units", :locale => options[:locale], :raise => true)
+        else
+          raise ArgumentError, ":units must be a Hash or String translation scope."
+        end.keys.map{|e_name| DECIMAL_UNITS.invert[e_name] }.sort_by{|e| -e}
+
+        number_exponent = Math.log10(number).floor
+        display_exponent = unit_exponents.find{|e| number_exponent >= e }
+        number  /= 10 ** display_exponent
+
+        unit = case units
+        when Hash
+          units[DECIMAL_UNITS[display_exponent]]
+        when String, Symbol
+          I18n.translate(:"#{units}.#{DECIMAL_UNITS[display_exponent]}", :locale => options[:locale], :count => number.to_i)
+        else
+          I18n.translate(:"number.human.decimal_units.units.#{DECIMAL_UNITS[display_exponent]}", :locale => options[:locale], :count => number.to_i)
+        end
+
+        decimal_format = options[:format] || I18n.translate(:'number.human.decimal_units.format', :locale => options[:locale], :default => "%n %u")
+        formatted_number = number_with_precision(number, options)
+        decimal_format.gsub(/%n/, formatted_number).gsub(/%u/, unit).strip
+      end
+
     end
   end
 end