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2847 :: Making a tuple of procvars is weird

• ggibson (orginal) [2017-03-12T07:32:25+01:00] view original

  Why does the first example below not work?

  ## First example
  type ProcSimple = proc(x:int)
  proc doSimple(x:int) {.procvar.} =
     echo "ran ok"
  
  var b:tuple[a:ProcSimple,b:ProcSimple]
  b = (a:doSimple,b:doSimple) ## Error: Mismatch
  b.a(0)
  Run

  The following is my workaround, by wrapping a procvar in a variable which is then used to create the tuple.

  ## Second example
  type ProcSimple = proc(x:int)
  proc doSimple(x:int) {.procvar.} =
     echo "ran ok"
  
  var b:tuple[a:ProcSimple,b:ProcSimple]
  var procRef:ProcSimple = doSimple ## this seems silly
  b = (a:procRef,b:procRef)
  b.a(0)
  Run

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• Araq (orginal) [2017-03-12T08:51:04+01:00] view original

  type ProcSimple = proc(x:int) {.nimcall.}

  Run

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• bluenote (orginal) [2017-03-12T09:09:38+01:00] view original

  I think explicit conversion would also work:

  var x: tuple[a: ProcSimple, b: ProcSimple]
  x = (
    a: doSimple.ProcSimple,
    b: doSimple.ProcSimple
  )
  Run

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