Add #pluralize_with_parenthesis to ActiveSupport::Inflector and Rails helpers. Example: 'article'.pluralize_with_parenthesis => 'article(s)' 'person'.pluralize_with_parenthesis => 'people'

pluralize_with_parenthesis.rb

module ActiveSupport
  module Inflector
    def pluralize_with_parenthesis(word)
      rule, replacement = find_inflections(word, inflections.plurals)
      if replacement =~ /\A\w+\Z/
        word.gsub!(rule, "(#{replacement})")
      else
        pluralize(word)
      end
    end

  private

    # find the inflection rules for +pluralize_with_parenthesis+.
    def find_inflections(word, rules)
      result = word.to_s.dup

      if word.empty? || inflections.uncountables.any? { |inflection| result =~ /\b#{inflection}\Z/i }
        false
      else
        replacements = rules.collect { |(rule, replacement)| [rule, replacement] if result.gsub!(rule, replacement) }.compact
        replacements.first
      end
    end    
  end
end

class String
  def pluralize_with_parenthesis
    ActiveSupport::Inflector.pluralize_with_parenthesis(self)
  end
end

module ActionView
  module Helpers
    module TextHelper
      def pluralize_with_parenthesis(word)
        word.pluralize_with_parenthesis
      end
    end
  end
end