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4032 :: Why `a, b = 0` fails?

• lucatrv (orginal) [2018-07-10T00:53:06+02:00] view original

  Is there a good reason why:

  var a, b = 0
  Run

  works but:

  var a, b: int
  a, b = 0
  Run

  fails?

  Is it possible to assign the same value to multiple defined variable?

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• blacpans (orginal) [2018-07-10T03:09:46+02:00] view original

  In the officical tutorial

  Note that declaring multiple variables with a single assignment which calls a procedure can have unexpected results: the compiler will unroll the assignments and end up calling the procedure several times. If the result of the procedure depends on side effects, your variables may end up having different values! For safety use only constant values.

  (https://nim-lang.org/docs/tut1.html#the-assignment-statement)

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• juancarlospaco (orginal) [2018-07-10T11:42:30+02:00] view original

  Redefinition error ?.

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• DeletedUser (orginal) [2018-07-10T16:29:10+02:00] view original

  I figure = is more an operator like + than builtin syntax like var sections. That would make it hard to parse a, b = 0 since you could expect = has more precedence than the comma, or there would be no simple proc implementation for it.

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• Stefan_Salewski (orginal) [2018-07-10T18:01:13+02:00] view original

  At least tuple assignment works:

  var a, b, c: int
  
  echo a, b, c
  (a, b, c) = (1, 1, 1)
  echo a, b, c
  
  Run

  
  stefan@nuc /tmp/hhh $ ./t
  000
  111
  
  Run

  And binary zero is already the default value for variables, unless {.noinit.} pragma is applied.

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• Vantage (orginal) [2018-07-10T20:26:33+02:00] view original

  var a, b = 0
  Run

  This doesn't work the way you seem to expect it to. it only assigns zero to b and ignores a. The type of b is int the default of a which infers its type based on what is assigned/declared to its right is int and the default of int is zero. You'd have different result if you did as follows:

  var a, b = 1
  echo a,b
  #01
  Run

  The following doesn't work because you can't unpack zero.

  var a, b: int
  a, b = 0
  Run

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• lucatrv (orginal) [2018-07-10T21:48:03+02:00] view original

  On my system using Nim 0.18.0 both on Linux and Windows I get:

  var a, b = 1
  echo a, b
  #11
  Run

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• Vantage (orginal) [2018-07-11T05:46:59+02:00] view original

  I don't know what to say :

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