Question

I have written a module similar to the following:

module One
  class Two
    def self.new(planet)
      @world = planet
    end
    def self.hello
      "Hello, #{@world}"
    end
  end
end

I was going to manipulate the module in the following way:

t = One::Two.new("World")
puts t.hello

Obviously, however, self.hello is not in t‘s scope. I realize that I could do the following:

t = One::Two
t.new("World")
puts t.hello

The previous method doesn’t feel right, so I am looking for an alternative.

Answer 1

module One
  class Two
    # use initialize, not self.new
    # the new method is defined for you, it creates your object
    # then it calls initialize to set the initial state.
    # If you want some initial state set, you define initialize.
    # 
    # By overriding self.new, One::Two.new was returning the planet,
    # not an initialized instance of Two.
    def initialize(planet)
      @world = planet
    end

    # because One::Two.new now gives us back an instance,
    # we can invoke it
    def hello
      "Hello, #{@world}"
    end
  end
end

t = One::Two.new 'World'
t.hello # => "Hello, World"