Question

I want to make DSL construction for my class something like

class Car 
  brand :mercedes
end

What code I need to write?

Answer 1

brand should be a method. It has to be defined somewhere. You have options: the very same class, parent class or mixed module. I like modules.

module MyDSL
  def brand name
    puts "Got brand #{name}"
  end
end

class Car 
  extend MyDSL

  brand :mercedes
end

# >> Got brand mercedes

While this answers your concrete question, I strongly recommend getting this book: Metaprogramming Ruby. Seems that you’ll find many answers there.