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1412 :: References of tuples?

• AxBen (orginal) [2015-07-06T11:45:14+02:00] view original

  Is there a way to have references of tuples, i.e. to have dynmically allocated tuples? Could the following code be made working?

  type
     ObjectRef = ref object
        oname: string
        otype: int
     
     TupleRef = ref tuple
        tname: string
        ttype: int
  
  var
     ods = newSeq[ObjectRef]()
     tds = newSeq[TupleRef]()
  
  ods.add(ObjectRef(oname: "Some object", otype: 4))
  tds.add(???(tname: "Some tuple", ttype: 5))
  
  Run

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• Jehan (orginal) [2015-07-06T20:02:01+02:00] view original

  Yes, with a helper function:

  proc box[T](arg: T): ref T {.inline.} =
    new result
    result[] = arg
  
  tds.add(box((tname: "foo", ttype: 0)))
  Run

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• AxBen (orginal) [2015-07-07T08:53:46+02:00] view original

  Thanks Jehan, but as I take if from the docs, new() creates an object, sth that I wanted to avoid (I'd also like to avoid using unmanaged storage though). Why isn't there anything like newTuple(...)?

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• takaomag (orginal) [2015-07-07T10:36:28+02:00] view original

  What about this?

  
  type
    TupleRef = ref tuple
      name: string
  
  
  proc newTupleRef(name: string): TupleRef =
    new(result)
    result.name = name
  
  
  var t = newTupleRef("tupleref")
  echo(repr(t))
  echo(repr(t[]))
  Run

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• AxBen (orginal) [2015-07-07T15:48:17+02:00] view original

  Thanks takaomag, but the question stands: W/o new() (and malloc()) is there a way to dynamically create a tuple?

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• Jehan (orginal) [2015-07-07T15:52:29+02:00] view original

  I'm not sure why you want to avoid new(). This is how you dynamically allocate an object; the object constructor version does the same, albeit implicitly.

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• jibal (orginal) [2015-07-07T22:52:52+02:00] view original

  AxBen: "new() creates an object, sth that I wanted to avoid (I'd also like to avoid using unmanaged storage though). Why isn't there anything like newTuple(...)?"

  The first thing that newAnything() does is call new(result). Your request doesn't appear to make sense ... a dynamically allocated tuple is a new object, so how can you ask for one without the other? If you don't want to call either new (which is for gc'ed objects) or alloc (which is for non-gc'ed objects), where do you expect the memory for the tuple to come from?

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• andrea (orginal) [2015-07-07T23:00:29+02:00] view original

  I think the misunderstanding is the word 'object'. new is used to allocate space a new object, whose type can be anything, not necessarily object. For instance, one can use new to allocate space for an array or a tuple

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• AxBen (orginal) [2015-07-21T14:27:17+02:00] view original

  @andrea

  Thx, now I've got it too...

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