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7360 :: Calling destructors works fine

• Stefan_Salewski (orginal) [2021-01-09T14:04:40+01:00] view original

  The gintro README contains still a warning from early ARC days that users may have to declare their own destructors if the intent to subclass widgets:

  https://github.com/StefanSalewski/gintro#extending-or-sub-classing-widgets

  But from a recent test I get the feeling that this is not really necessary any more. With modules tt.nim and t.nim I get:

  # module tt.nim
  type
    O1* = ref object of Rootref
      i*: int
  
  when defined(gcDestructors):
    proc `=destroy`(o1: var typeof(O1()[])) =
      echo "destroy O1 ", typeof(o1)
  Run

  module t.nim
  import tt
  
  type
    O2 = ref object of tt.O1
      j: int
  
  type
    O3 = ref object
      o1: tt.O1
  
  type
    O4 = object
      o1: tt.O1
  
  proc main =
    var o1: tt.O1
    new o1
    echo o1.i
    
    var o2: O2
    new o2
    echo o2.j
    
    var o3: O3
    new o3
    new o3.o1
    
    var o4: O4
    new o4.o1
  
  main()
  Run

  
  salewski@nuc /tmp/hhh $ ./t
  0
  0
  destroy O1 O1:ObjectType
  destroy O1 O1:ObjectType
  destroy O1 O1:ObjectType
  destroy O1 O1:ObjectType
  Run

  So the destructor is always called for the parent base class, no need for users to declare own destructors any more. Is this new for latest Nim 1.4?

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