refactoring patterns

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# = Extract Superclass
#
# == Before Refactor
class Department
  attr_reader :total_annual_cost, :name, :head_count
end

class Employee
  attr_reader :annual_cost, :name, :id
end

# == After "Extract Superclass" Refactoring
class Party
  attr_reader :annual_cost, :name
end

class Employee < Party
  attr_reader :id
end

class Department < Party
  attr_reader :head_count
end

# == After "Extract Superclass" (using module)
module Party
  attr_reader :annual_cost, :name
end

class Employee
  include Party

  attr_reader :id
end

class Department
  include Party

  attr_reader :head_count
end


# = Replace Nested Conditional with Guard Clauses
#
# == Before Refactoring
def get_payment_amount
  if dead?
    result = dead_amount
  elsif separated?
    result separated_amount
  elsif retired?
    result retired_amount
  else
    result = normal_pay_amount
  end

  result
end

# == After Refactoring
def get_payment_amount
  return dead_amount     if dead?
  return separted_amount if separated?
  return retired_amount  if retired?
  normal_pay_amount
end