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4537 :: Initializing inherited types in Nim VM

• chrisheller (orginal) [2019-01-06T10:40:48+01:00] view original

  This is a boiled down test from another thread about using the pegs module at compile time. I thought I would throw this out there since there seems to be some general CTFE interest going on right now. I poked around in the VM code to see if I could figure out why the inherited type initialization doesn't work, but I wasn't successful in the (small) amount of time that I spent on it.

  # test of initializing inherited types in VM
  type
    SomeBaseObj  {.inheritable.} = object of RootObj
      txt : string
    
    InheritedFromBase = object of SomeBaseObj
      other : string
  
  proc initBase(sbo: var SomeBaseObj) =
    sbo.txt = "Initialized string from base"
  
  proc initInherited(ifb: var InheritedFromBase) =
    ifb.txt = "Initialized string from inherited"
  
  static:
    var bo: SomeBaseObj
    initBase(bo)
    doAssert(bo.txt == "Initialized string from base")
    
    var ifb1: InheritedFromBase
    initInherited(ifb1)
    doAssert(ifb1.txt == "Initialized string from inherited")
    
    var ifb2: InheritedFromBase
    initBase(SomeBaseObj(ifb2))
    # This assertion passes because ifb2 gets re-initialized
    doAssert(ifb2.txt == "")
  
  echo "Done"
  Run

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• chrisheller (orginal) [2019-03-21T06:57:15+01:00] view original

  By the way, this is now working properly on devel builds.

  # test of initializing inherited types in VM
  type
    SomeBaseObj  {.inheritable.} = object of RootObj
      txt : string
    
    InheritedFromBase = object of SomeBaseObj
      other : string
  
  proc initBase(sbo: var SomeBaseObj) =
    sbo.txt = "Initialized string from base"
  
  proc initInherited(ifb: var InheritedFromBase) =
    ifb.txt = "Initialized string from inherited"
  
  static:
    var bo: SomeBaseObj
    initBase(bo)
    doAssert(bo.txt == "Initialized string from base")
    
    var ifb1: InheritedFromBase
    initInherited(ifb1)
    doAssert(ifb1.txt == "Initialized string from inherited")
    
    var ifb2: InheritedFromBase
    initBase(SomeBaseObj(ifb2))
    # This assertion now passes because ifb2 does not get re-initialized
    echo ifb2.txt
    doAssert(ifb2.txt == "Initialized string from base")
  
  echo "Done"
  
  Run

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