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5786 :: `=destroy` is called for ref types when compiled with --gc:arc :-)

• Stefan_Salewski (orginal) [2020-01-09T16:00:19+01:00] view original

  I think I heard about that in nim forum long time ago, but tested only with default gc, where destroy is not called. But with ARC it is called indeed currently, and gc_ref/unref seems to work also, so gintro and other packages using finalizers may survive.

  type
    O = object
      i: int
    
    R = ref O
  
  proc `=destroy`(x: var O) =
    echo "destroy"
  
  proc main =
    var r = R(i: 7)
    echo r.i
    GC_ref(r)
    GC_unref(r)
  main()
  Run

  
  $ nim c --gc:arc t.nim
  $ ./t
  7
  destroy
  Run

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• mratsim (orginal) [2020-01-09T17:12:46+01:00] view original

  But the goal is to unify finalizers and destructors.

  I'm not sure what's the best way for the transition, maybe have destroy= call the finalizer but wrap it in a since versioning block. And the new for your ref types has a since as well to not use the finalizer. But it's indeed a bit involved.

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