number_localization.rb

class String
  def to_delocalized_decimal
    delimiter = I18n::t('number.format.delimiter')
    separator = I18n::t('number.format.separator')
    self.gsub(/[#{delimiter}]/, '').gsub(separator, '.')
  end

  def to_delocalized_money
    unit = I18n::t('number.currency.format.unit')
    delimiter = I18n::t('number.currency.format.delimiter')
    separator = I18n::t('number.currency.format.separator')
    self.gsub(/[#{unit} ?#{delimiter}]/, '').gsub(separator, '.')
  end  
end

class ActiveRecord::Base
  def self.localized_number(*fields)
    fields.each do |field|
      define_method("#{field}=") do |value|
        self[field] = value.is_a?(String) ? value.to_delocalized_decimal : value
      end
    end
  end

  def self.localized_money(*fields)
    fields.each do |field|
      define_method("#{field}=") do |value|
        self[field] = value.is_a?(String) ? value.to_delocalized_money : value
      end
    end
  end  
end