has.rb

  C = Class.new do
    def has?(methods)
      !!methods.split(".").inject(self) do |object, method|
        object.respond_to?(method) && object.send(method)
      end
    end
  end
  
  c = C.new
  c.has?("methods") # => true
  c.has?("methods.reverse") # => true
  c.has?("methods.reverse.first") # => true
  c.has?("methods.reverse.foo") # => false