delegator_example.rb

require 'delegate'

class NumberDecorator < SimpleDelegator

  def in_dollars
    "$#{to_s}"
  end

  def in_euros
    "€#{to_s}"
  end

  def in_pounds
    "£#{to_s}"
  end

  # Any other method will be delegated to the wrapped object
end

amount = NumberDecorator.new(13.5)

puts amount.in_dollars
# => $13.5

puts amount.in_pounds
# => £13.5

puts amount.floor # method delegated to the 13.5 Float object
# => 13

puts amount.ceil # another delegated method
# => 14

# Change the wrapped object, if you want
amount.__setobj__(24.8)

puts amount.in_dollars
# => $24.8