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10347 :: Concepts in Nim v2

• TKD (orginal) [2023-07-22T15:27:31+02:00] view original

  Is 'concepts' is being polished/refurbished as a major feature in v2 - I hope it is.

  I am assuming the code below is a known problem; compilation is slow and nothing is produced as output. This is on devel 1.9.5.

  type
    Distribution = concept
      proc sample(d: Self): float
    
    Die[float] = object
      sides: int
  
  func sample(d: Distribution): float =
    rand(1..d.sides)
  
  
  let D = Die[float](sides: 6)
  echo sample D
  Run

  nim

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• sls1005 (orginal) [2023-07-22T16:11:57+02:00] view original

  It's like saying "sample takes a Distribution, which could be anything that can be given to sample."

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• Calonger (orginal) [2023-07-22T16:53:08+02:00] view original

  `` Die[float] = object `` mean what ?? Float is not generic parameter !

  func sample(d: Distribution): float =

  rand(1..d.sides)

  This infinite recursive definition ! Distribution not concrete type ! Need use Die !

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• TKD (orginal) [2023-07-22T17:10:03+02:00] view original

  Yes, it is defining a distribution as something that can be sampled.

  In the old form of 'concepts', this would be an infinite recursion as has been explained to me already in some other thread but my understanding is that in this new, unfinished form of 'concepts', procs with a Self parameter are allowed.

  So, as long as the concrete type can be sampled, it should work.

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• TKD (orginal) [2023-07-22T17:12:22+02:00] view original

  Then, there is no need for the concept if I use 'Die'. See my reply to sls1005.

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• TKD (orginal) [2023-07-22T17:55:23+02:00] view original

  My misunderstanding! I fixed this now. It should indeed be 'Die' as the sample parameter.

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• Calonger (orginal) [2023-07-22T17:56:20+02:00] view original

  You need use Die to make Die Distribution. You not define sample on Die , you define sample for Distribution , which infinite recursive ( define sample for type with sample defined ???????? )

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• termer (orginal) [2023-07-25T15:47:41+02:00] view original

  New-style concepts are super broken right now, and concepts in general are unusable when you're trying to use generics. Believe me, I've tried. I'd be really happy if there was an overhaul of concepts in v2, but I don't expect it.

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• Araq (orginal) [2023-07-25T18:16:33+02:00] view original

  Don't worry, I do believe you. Now where is this Nim server of yours that supports streaming?

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• termer (orginal) [2023-07-25T19:00:09+02:00] view original

  @Araq Hahaha you haven't forgotten, eh. I'm using microasynchttpserver in some limited projects to see how it does. Time is lacking these days, but I've also played around with disruptek's CPS project and webserver implemented in it, which performs extremely well. I wouldn't mind building streaming I/O on top of that, since it's way more solid than asyncdispatch or even Chronos.

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