type SeqView[T] = object data: ref seq[T] bounds: Slice[int] proc seqView*[T](x: seq[T], bounds: Slice): SeqView[T] = var rf: ref seq[T] new(rf) shallowCopy(rf[], x) # beware :) SeqView[T](data: rf, bounds: bounds) iterator items*[T](sv: SeqView[T]): T = for pos in sv.bounds: yield sv.data[pos] iterator mitems*[T](sv: SeqView[T]): var T = for pos in sv.bounds: yield sv.data[pos] var seq1 = @[1, 2, 3, 4, 5, 6] sv = seqView(seq1, 2..4) echo "a:" for el in sv: echo el # inc using the mitems on the "slice" for el in mitems(sv): inc el echo "\nb:" for el in sv: echo el # update and print original data for i in 2..4: inc seq1[i] echo "\nc:" for el in seq1: echo el echo "\nd:" # test if true reference or copy for el in sv: echo el