Module: Monee::Arithmetic

Included in:
Money
Defined in:
lib/monee/arithmetic.rb

Overview

modularizing the arithmetic related methods in a separate module for money

Instance Method Summary collapse

Instance Method Details

#choose_operand(operator, operand) ⇒ Numeric

convert to cents if add or subtract dont convert to cents if multiply or divide

Returns:



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# File 'lib/monee/arithmetic.rb', line 32

def choose_operand(operator, operand)
  if %i[+ -].include?(operator)
    operand.to_cents
  elsif %i[* /].include?(operator)
    operand
  end
end

#coerce(other) ⇒ Object

this method is to support the order of the operation 2 * Monee::Money.new(50, ‘EUR’)



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# File 'lib/monee/arithmetic.rb', line 42

def coerce(other)
  return self, other
end

#operator ⇒ Money

metaprogramming way of defining methods

overloads the operators with 2 operands adds amount/cents if number converts to the currency and calculates if money object

Returns:



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# File 'lib/monee/arithmetic.rb', line 10

%i[+ - * /].each do |operator|
  define_method(operator) do |operand|
    result_cents = case operand
                   when ::Numeric
                     cents.send(operator,
                                choose_operand(operator, operand))
                   when klass
                     cents.send(operator,
                                operand.convert_to_cents(currency))
                   else
                     raise InvalidOperand
                   end
    amount = result_cents.to_amount
    klass.new(amount, currency)
  end
end