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2199 :: Nim Tutorial (Part I) ->varargs

• bigsnail (orginal) [2016-04-10T15:31:55+02:00] view original

  proc myWriteln(f: File, a: varargs[string]) =
    for s in items(a):
      write(f, s)
    write(f, "\n")
  
  myWriteln(stdout, "abc", "def", "xyz")
  # is transformed by the compiler to:
  myWriteln(stdout, ["abc", "def", "xyz"])
  Run

  This transformation is only done if the varargs parameter is the last parameter in the procedure header. but

  proc myWriteln(a:varargs[string],b:string)=
    for i in 0..len(a)-1:
      echo a[i]
  
  myWriteln("abc","def","xyz","123")
  Run

  This case is also correct!　So how to understand varargs parameter？

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• Arrrrrrrrr (orginal) [2016-04-10T16:19:33+02:00] view original

  The last argument, "123", is assigned to b, which is ignored by your code. By the way, the order of varags position does not matter, try: proc myWriteln(a: varargs[string], f: File) and myWriteln("abc", "def", "xyz", stdout)

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• gentius (orginal) [2016-04-10T16:32:14+02:00] view original

  Couldn't render post #13464.

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• bigsnail (orginal) [2016-04-11T03:36:12+02:00] view original

  proc myWriteln(a:varargs[string],b:string)=
    for i in 0..len(a)-1:
      echo a[i]
    echo b
  
  myWriteln("abc","def","xyz","123")
  Run

  This is also correct!

  proc myWriteln(a:varargs[string],f:File)=
    for s in items(a):
      writeln(f,s)
  
  myWriteln("abc","def","xyz",stdout)
  Run

  I don't think there will be a problem, I just don't understand this sentence!

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