self and class<< in ruby

October 04, 2022

You can use class << self, self.method or className.method for class method

class Project
  def initialize(project_name)
    @project_name = project_name
  end

  def project_name
    "#{@project_name}"
  end

  def self.who
    "Ruby Project class"
  end

  def Project.who2
    "Ruby Project class 2"
  end 

  class << self
    def who3
      "Ruby Project class 3"
    end
  end
end

project = Project.new("Ruby Demo")
puts project.project_name
puts Project.who
puts Project.who2
puts Project.who3