Money

Use this to enable the ability to assume the currency from a passed symbol

@return [true,false]

Use this to specify precision for converting Rational to BigDecimal

@return [Integer]

Each Money object is associated to a bank object, which is responsible for currency exchange. This property allows you to specify the default bank object. The default value for this property is an instance of +Bank::VariableExchange.+ It allows one to specify custom exchange rates.

@return [Money::Bank::*]

The default currency, which is used when Money.new is called without an explicit currency argument. The default value is Currency.new("USD"). The value must be a valid +Money::Currency+ instance.

@return [Money::Currency]

Use this to enable infinite precision cents

@return [true,false]

Use this to specify the rounding mode

@return [BigDecimal::ROUND_MODE]

Use this to disable i18n even if it's used by other objects in your app.

@return [true,false]

The +Money::Bank+ based object used to perform currency exchanges with.

@return [Money::Bank::*]

The currency the money is in.

@return [Currency]

Adds a new exchange rate to the default bank and return the rate.

@param [Currency, String, Symbol] from_currency Currency to exchange from. @param [Currency, String, Symbol] to_currency Currency to exchange to. @param [Numeric] rate Rate to exchange with.

@return [Numeric]

@example

Money.add_rate("USD", "CAD", 1.25) #=> 1.25

# File lib/money/money.rb, line 212
def self.add_rate(from_currency, to_currency, rate)
  Money.default_bank.add_rate(from_currency, to_currency, rate)
end

Creates a new Money object of the given value, using the Canadian dollar currency.

@param [Integer] cents The cents value.

@return [Money]

@example

n = Money.ca_dollar(100)
n.cents    #=> 100
n.currency #=> #<Money::Currency id: cad>

# File lib/money/money.rb, line 132
def self.ca_dollar(cents)
  Money.new(cents, "CAD")
end

Create a new money object with value 0.

@param [Currency, String, Symbol] currency The currency to use.

@return [Money]

@example

Money.empty #=> #<Money @fractional=0>

# File lib/money/money.rb, line 117
def self.empty(currency = default_currency)
  Money.new(0, currency)
end

Creates a new Money object of the given value, using the Euro currency.

@param [Integer] cents The cents value.

@return [Money]

@example

n = Money.euro(100)
n.cents    #=> 100
n.currency #=> #<Money::Currency id: eur>

# File lib/money/money.rb, line 161
def self.euro(cents)
  Money.new(cents, "EUR")
end

Creates a new Money object of value given in the +fractional unit+ of the given currency.

Alternatively you can use the convenience methods like {Money.ca_dollar} and {Money.us_dollar}.

@param [Integer] The value given in the fractional unit. @param [Currency, String, Symbol] currency The currency format. @param [Money::Bank::*] bank The exchange bank to use.

@return [Money]

@example

Money.new(100)
#=> #<Money @fractional=100 @currency="USD">
Money.new(100, "USD")
#=> #<Money @fractional=100 @currency="USD">
Money.new(100, "EUR")
#=> #<Money @fractional=100 @currency="EUR">

@see Money.new_with_dollars

# File lib/money/money.rb, line 239
def initialize(fractional, currency = Money.default_currency, bank = Money.default_bank)
  @fractional = if fractional.is_a?(Rational)
                  fractional.to_d(self.class.conversion_precision)
                elsif fractional.respond_to?(:to_d)
                  fractional.to_d
                else
                  BigDecimal.new(fractional.to_s)
                end
  @currency = Currency.wrap(currency)
  @bank     = bank
end

Creates a new Money object of amount value , with given currency.

The amount value is expressed in the main monetary unit, opposite to the subunit-based representation used internally by this library called cents.

@param [Numeric] amount The money amount, in main monetary unit. @param [Currency, String, Symbol] currency The currency format. @param [Money::Bank::*] bank The exchange bank to use.

@return [Money]

@example

Money.new_with_amount(100)
#=> #<Money @fractional=10000 @currency="USD">
Money.new_with_amount(100, "USD")
#=> #<Money @fractional=10000 @currency="USD">
Money.new_with_amount(100, "EUR")
#=> #<Money @fractional=10000 @currency="EUR">

@see Money.new

# File lib/money/money.rb, line 188
def self.new_with_amount(amount, currency = Money.default_currency, bank = Money.default_bank)
  money = from_numeric(amount, currency)
  # Hack! You can't change a bank
  money.instance_variable_set("@bank", bank)
  money
end

Synonym of new_with_amount

@see Money.new_with_amount

# File lib/money/money.rb, line 198
def self.new_with_dollars(*args)
  self.new_with_amount(*args)
end

Creates a new Money object of the given value, using the American dollar currency.

@param [Integer] cents The cents value.

@return [Money]

@example

n = Money.us_dollar(100)
n.cents    #=> 100
n.currency #=> #<Money::Currency id: usd>

# File lib/money/money.rb, line 147
def self.us_dollar(cents)
  Money.new(cents, "USD")
end

Allocates money between different parties without loosing pennies. After the mathmatically split has been performed, left over pennies will be distributed round-robin amongst the parties. This means that parties listed first will likely recieve more pennies then ones that are listed later

@param [0.50, 0.25, 0.25] to give 50% of the cash to party1, 25% ot party2, and 25% to party3.

@return [Array<Money, Money, Money>]

@example

Money.new(5, "USD").allocate([0.3,0.7)) #=> [Money.new(2), Money.new(3)]
Money.new(100, "USD").allocate([0.33,0.33,0.33]) #=> [Money.new(34), Money.new(33), Money.new(33)]

# File lib/money/money.rb, line 477
def allocate(splits)
  allocations = splits.inject(BigDecimal("0")) do |sum, n|
    n = BigDecimal(n.to_s) unless n.is_a?(BigDecimal)
    sum + n
  end

  if (allocations - BigDecimal("1")) > Float::EPSILON
    raise ArgumentError, "splits add to more then 100%"
  end

  left_over = fractional

  amounts = splits.map do |ratio|
    if self.class.infinite_precision
      fraction = fractional * ratio
    else
      fraction = (fractional * ratio / allocations).floor
      left_over -= fraction
      fraction
    end
  end

  unless self.class.infinite_precision
    left_over.to_i.times { |i| amounts[i % amounts.length] += 1 }
  end

  amounts.collect { |fractional| Money.new(fractional, currency) }
end

Returns the numerical value of the money

@return [Float]

@example

Money.new(100).amount            # => 1.0
Money.new_with_amount(1).amount  # => 1.0

@see to_f @see fractional

# File lib/money/money.rb, line 282
def amount
  to_f
end

Receive a money object with the same amount as the current Money object in canadian dollar.

@return [Money]

@example

n = Money.new(100, "USD").as_ca_dollar
n.currency #=> #<Money::Currency id: cad>

# File lib/money/money.rb, line 449
def as_ca_dollar
  exchange_to("CAD")
end

Receive a money object with the same amount as the current Money object in euro.

@return [Money]

@example

n = Money.new(100, "USD").as_euro
n.currency #=> #<Money::Currency id: eur>

# File lib/money/money.rb, line 461
def as_euro
  exchange_to("EUR")
end

Receive a money object with the same amount as the current Money object in american dollars.

@return [Money]

@example

n = Money.new(100, "CAD").as_us_dollar
n.currency #=> #<Money::Currency id: usd>

# File lib/money/money.rb, line 437
def as_us_dollar
  exchange_to("USD")
end

Convenience method for fractional part of the amount. Synonym of fractional

@return [Integer]

# File lib/money/money.rb, line 16
def cents
  fractional
end

Return string representation of currency object

@return [String]

@example

Money.new(100, :USD).currency_as_string #=> "USD"

# File lib/money/money.rb, line 292
def currency_as_string
  currency.to_s
end

Set currency object using a string

@param [String] val The currency string.

@return [Money::Currency]

@example

Money.new(100).currency_as_string("CAD") #=> #<Money::Currency id: cad>

# File lib/money/money.rb, line 304
def currency_as_string=(val)
  @currency = Currency.wrap(val)
end

Assuming using a currency using dollars: Returns the value of the money in dollars, instead of in the fractional unit cents.

Synonym of amount

@return [Float]

@example

Money.new(100).dollars           # => 1.0
Money.new_with_dollars(1).dollar # => 1.0

@see amount @see to_f @see cents

# File lib/money/money.rb, line 267
def dollars
  amount
end

Receive the amount of this money object in another Currency.

@param [Currency, String, Symbol] other_currency Currency to exchange to.

@return [Money]

@example

Money.new(2000, "USD").exchange_to("EUR")
Money.new(2000, "USD").exchange_to(Currency.new("EUR"))

# File lib/money/money.rb, line 424
def exchange_to(other_currency)
  other_currency = Currency.wrap(other_currency)
  @bank.exchange_with(self, other_currency)
end

The value of the amount represented in the fractional unit of the currency. Example: USD, 1 dollar (amount) == 100 cents (fractional unit).

@return [Integer]

# File lib/money/money.rb, line 23
def fractional
  if self.class.infinite_precision
    @fractional
  else
    # If the Money object is created from a serialized YAML string, 
    # @fractional can end up being set to a Float. We need to ensure 
    # it is BigDecimal before calling #round with two paramers. 
    # Float class only provides #round with 0 or 1 parameter.
    BigDecimal.new(@fractional.to_s, 0).round(0, self.class.rounding_mode).to_i
  end
end

Returns a Fixnum hash value based on the fractional and currency attributes in order to use functions like & (intersection), group_by, etc.

@return [Fixnum]

@example

Money.new(100).hash #=> 908351

# File lib/money/money.rb, line 315
def hash
  [fractional.hash, currency.hash].hash
end

Common inspect function

@return [String]

# File lib/money/money.rb, line 332
def inspect
  "#<Money fractional:#{fractional} currency:#{currency}>"
end

Split money amongst parties evenly without loosing pennies.

@param [2] number of parties.

@return [Array<Money, Money, Money>]

@example

Money.new(100, "USD").split(3) #=> [Money.new(34), Money.new(33), Money.new(33)]

# File lib/money/money.rb, line 514
def split(num)
  raise ArgumentError, "need at least one party" if num < 1

  if self.class.infinite_precision
    amt = self.div(BigDecimal(num.to_s))
    return 1.upto(num).map{amt}
  end

  low = Money.new(fractional / num, self.currency)
  high = Money.new(low.fractional + 1, self.currency)

  remainder = fractional % num
  result = []

  num.times do |index|
    result[index] = index < remainder ? high : low
  end

  result
end

Uses +Currency#symbol+. If nil is returned, defaults to "¤".

@return [String]

@example

Money.new(100, "USD").symbol #=> "$"

# File lib/money/money.rb, line 325
def symbol
  currency.symbol || "¤"
end

Return the amount of money as a BigDecimal.

@return [BigDecimal]

@example

Money.us_dollar(100).to_d => BigDecimal.new("1.0")

# File lib/money/money.rb, line 386
def to_d
  BigDecimal.new(fractional.to_s) / BigDecimal.new(currency.subunit_to_unit.to_s)
end

Return the amount of money as a float. Floating points cannot guarantee precision. Therefore, this function should only be used when you no longer need to represent currency or working with another system that requires decimals.

@return [Float]

@example

Money.us_dollar(100).to_f => 1.0

# File lib/money/money.rb, line 399
def to_f
  to_d.to_f
end

Conversation to self.

@return [self]

# File lib/money/money.rb, line 406
def to_money(given_currency = nil)
  given_currency = Currency.wrap(given_currency) if given_currency
  if given_currency.nil? || self.currency == given_currency
    self
  else
    exchange_to(given_currency)
  end
end

Returns the amount of money as a string.

@return [String]

@example

Money.ca_dollar(100).to_s #=> "1.00"

# File lib/money/money.rb, line 342
def to_s
  unit, subunit = fractional().abs.divmod(currency.subunit_to_unit)

  unit_str       = ""
  subunit_str    = ""
  fraction_str   = ""

  if self.class.infinite_precision
    subunit, fraction = subunit.divmod(BigDecimal("1"))

    unit_str       = unit.to_i.to_s
    subunit_str    = subunit.to_i.to_s
    fraction_str   = fraction.to_s("F")[2..-1] # want fractional part "0.xxx"

    fraction_str = "" if fraction_str =~ /^0+$/
  else
    unit_str, subunit_str = unit.to_s, subunit.to_s
  end

  absolute_str = if currency.decimal_places == 0
    if fraction_str == ""
      unit_str
    else
      "#{unit_str}#{decimal_mark}#{fraction_str}"
    end
  else
    # need to pad subunit to right position,
    # for example 1 usd 3 cents should be 1.03 not 1.3
    subunit_str.insert(0, '0') while subunit_str.length < currency.decimal_places

    "#{unit_str}#{decimal_mark}#{subunit_str}#{fraction_str}"
  end

  absolute_str.tap do |str|
    str.insert(0, "-") if fractional() < 0
  end
end