Ruby’s ‘private_constant’ method

https://ruby-doc.org/3.3.6/Module.html#method-i-private_constant

If you want to define a constant, but keep it private and inaccessible to anything outside of your current class or module definition, you can use the Module#private_constant method. An example of this is demonstrated on Aaron Lasseigne’s blog:

class Broccoli
  FAMILY = 'cabbage'
  WORST_PART = 'stem'
  private_constant :WORST_PART

  def worst_part?
    WORST_PART
  end
end

By setting WORST_PART as private, you cannot access that constant from outside of the Broccoli class or methods:

Broccoli::FAMILY #=> 'cabbage'

Broccoli::WORST_PART
private constant Broccoli::WORST_PART referenced (NameError)

Broccoli::WORST_PART
        ^^^^^^^^^^^^

Broccoli.new.worst_part? #=> "stem"