You can freeze classes in ruby

freeze_class.rb

class Point
  attr_reader :x, :y

  def initialize(x, y)
    @x = x
    @y = y
    freeze
  end

  def move!(x_offset, y_offset)
    @x = x + x_offset
    @y = y + y_offset
  end

  def move(x_offset, y_offset)
    Point.new(x + x_offset, y + y_offset)
  end
end

p = Point.new(10, 10)
p.move(-5, -5)

p = Point.new(5, 5)
p.move!(5, 5) 
# => can't modify frozen Point (FrozenError)