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10387 :: How Can I Ensure Backward Compatibility with Destructors in Nim 2.0?

• Ward (orginal) [2023-08-08T15:41:19+02:00] view original

  In Nim 2.0, destructors now accept a parameter of type T instead of var T. Are there any recommended approaches to maintaining backward compatibility in existing code?

  My attempt was:

  when compiles(block:
      type O = object
      proc `=destroy`(self: O) = discard
    ):
    const newDestructors = true
  else:
    const newDestructors = false
  Run

  And then writing two versions of destructors for the object.

  Is there a more optimal solution?

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• Araq (orginal) [2023-08-08T17:22:33+02:00] view original

  Use a version check like when (NimMajor, NimMinor) >= (2, 0)

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• Ward (orginal) [2024-01-03T03:43:50+01:00] view original

  Based on information from https://forum.nim-lang.org/t/10807, I believe a more suitable approach would be to use when defined(nimAllowNonVarDestructor) and not defined(gcRefc)

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• Ward (orginal) [2024-07-12T19:07:00+02:00] view original

  The system libs seems use

  
      const arcLike = defined(gcArc) or defined(gcAtomicArc) or defined(gcOrc)
      when defined(nimAllowNonVarDestructor) and arcLike:
          ...
  Run

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• Araq (orginal) [2024-07-12T19:19:48+02:00] view original

  Correct, use that. :-)

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