using method missing to reduce the code in ruby

Question

I have a set of Class methods which is :

class << self
def increment_value
  self.first.increment_value
end

def max_work_hours_per_day
  self.first.max_work_hours_per_day
end

def fast_completion_day
  self.first.fast_completion_day
end

def super_fast_completion_day
  self.first.super_fast_completion_day
end

def ludicrous_completion_day
  self.first.ludicrous_completion_day
end

def budget_completion_day
  self.first.budget_completion_day
end
end

Since all the methods call self.first.atttibute where attribute is the same name as function name. I think we can reduce this to a single method. Something like method_missing is there in Ruby , but since I am not very good at meta programming , I am seeking advise here.

Answer 1

Ruby already has a module which allows you to forward specific methods to a given object in its standard library: the Forwardable module.

Using it you can write code like this:

class << self
  extend Forwardable

  def_delegators :first, :increment_value, :max_work_hours_per_day #...
end

I think spelling out the methods you want to forward like this is preferable to simply forwarding everything as it won't accidentally forward something you don't want to forward. It also does not affect the error message when calling a method that does not exist.