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5975 :: How to use integer generics in types?

• stevejock1 (orginal) [2020-02-24T08:14:47+01:00] view original

  type

  MatchPool[N] = object # Here, N is an integer

  vals: array[N, int]

  var mp = MatchPool3 Also, can I create new MatchPool of certain int in runtime in the heap? (N is not known in compile time)

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• DeletedUser (orginal) [2020-02-24T10:24:37+01:00] view original

  To straight up give an example it's like this:

  type MatchPool[N: static[int]] = object
    vals: array[N, int]
  
  var mp = MatchPool[3](vals: [2, 4, 1])
  Run

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• cblake (orginal) [2020-02-24T13:38:38+01:00] view original

  There's no easy way to provide default values for such integer generic parameters, is there? E.g. (this doesn't work):

  type MatchPool[N: static[int] = 3] = object ....
  Run

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• sekao (orginal) [2020-02-26T12:37:58+01:00] view original

  I'm glad i came across this thread, because i ran into a very ugly error with:

  type
    Thing[I] = object
      things: array[I, int]
  
  echo Thing[5]()
  
  # Error: unhandled exception: int128.nim(72, 11) `arg.sdata(2) == 0` out of range [AssertionError]
  Run

  Changing it to Thing[I: static[int]] fixes it but the error made me think i hit a compiler bug.

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