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5335 :: Throw-away variables?

• nroach2 (orginal) [2019-10-11T23:12:26+02:00] view original

  Hi all, I'm relatively new to nim. I'm wondering if there's an equivalent to the _ variable name in python, something that allows us to throw away individual values of a tuple when it's being unpacked. For example, if I had a proc that returns three values packaged as a tuple, is there a way to tell the interpreter to throw away two of those three values? The discard statement doesn't seem to work for this purpose. I've done some searching and it doesn't seem like anything like that exists, but I thought I'd check here before I gave up and assigned it to a variable that won't end up being used. Thanks in advance!

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• mratsim (orginal) [2019-10-12T00:42:27+02:00] view original

  You can use _ like in Python

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• htorun (orginal) [2019-10-13T01:46:33+02:00] view original

  I think this is what you are looking for: https://nim-lang.org/docs/manual.html#statements-and-expressions-tuple-unpacking

  proc returnsTuple(): (int, int, int) = (4, 2, 3)
  
  let (x, _, z) = returnsTuple()
  
  # apparently this only works for "let" or "var" statements but not for assignments
  var
    a, b, c: int
  
  (a, b, c) = returnsTuple() # works
  (a, _, c) = returnsTuple() # this (obviously ?) does NOT work
  Run

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• miran (orginal) [2019-10-13T08:16:15+02:00] view original

  Related: if you want to unpack other datatype, there is unpack package: https://github.com/technicallyagd/unpack

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