How_Passed_Instance_Vars.cr

class Some
  property s : String, ai : Array(Int32)

  def initialize(@s : String, *some_ints)
    @ai = [] of Int32
    some_ints.each { |e|
      if e.is_a?(Int32)
        @ai << e
      end
    }
  end

  def s_addr
    @s.to_unsafe.address
  end

  def ai_dump
    p @ai
  end
end

obj = Some.new("kis-kis", 1, 2, 3)
copy_of_s = obj.s
ps = pointerof(copy_of_s)

puts %(Address in memory of "copied" s: #{copy_of_s.to_unsafe.address})
puts %(Address in memory of instance variable stored inside object: #{obj.s_addr})
puts %("copied" s and instance variable is ) + (copy_of_s.to_unsafe.address == obj.s_addr ? "absolutely" : "not") + " the same"

l = obj.ai
puts %(Array inside object before change to its "copy")
obj.ai_dump
l[0] = 7
puts %(Array inside object after change to its "copy")
obj.ai_dump