CrazyMoney

This is a simplier version of the Money class which comes with the Money Gem.

It doesn't try to handle currency conversions but simply wraps an amount of money into a BigDecimal instance to avoid precision issues with floating point arithmetic operations.

Features:

• doesn't monkey-patch Ruby core types
• less than 100 lines of code
• currency formatting support, e.g. CrazyMoney.new("1234.56").with_currency("NZD") #=> "$1,234.56"
• easy to integrate with Rails (see Rails)

Usage

amount = CrazyMoney.new("13.37")
amount > 1 #=> true
amount == 13 #=> false
amount == 13.37 #=> true
amount == CrazyMoney.new(13.37) #=> true
amount.cents.to_i #=> 1337
amount.with_currency("NZD") #=> "$13.37"

Rails

At the moment, there is no built-in support for Rails but you can use this initializer as a drop-in replacement for the monetize helper that is provided by the Money Gem.

# config/initializers/crazy_money.rb

class ActiveRecord::Base
  class << self
    def monetize attribute_cents
      attribute = attribute_cents.to_s.sub(/_cents$/, "")

      define_method attribute do
        CrazyMoney.new(send(attribute_cents)) / 100
      end

      define_method "#{attribute}=" do |value|
        send("#{attribute_cents}=", CrazyMoney.new(value).cents)
      end
    end
  end
end