c:\64\nimrod\lib\system.nim(390, 13) Error: cannot instantiate: 'T'

itertools.nim

iterator cycle* [iterType, returnType](iter:iterType): returnType =
  ## An iterator returning elements from the iterable and saving a 
  ## copy of each. When the iterable is exhausted, return elements 
  ## from the saved copy. Repeats indefinitely.
  ##
  ## Parameters:
  ##   iter: The iterator to cycle through
  var cont:seq[returnType]
  cont = newSeq[returnType]()
  for element in iter:
    yield element
    cont.add(element)
  while True:
    for element in cont:
      yield element

when defined(isMainModule):
  var cycleSeq = @[1,2]
  var cycleIterator = cycle[seq[int], int]
  for i in 1..3:
    cycleSeq.add(cycleIterator(cycleSeq))
  assert(cycleSeq == @[1,2,1,2,1,2])
  echo(repr(cycleSeq))
#