On Thursday, 14 June 2018 at 11:31:50 UTC, Robert M. Münch wrote: > Is this possible? I read about Inputranges, took a look at the > RBTree code etc. but don't relly know/understand where to start. You can also use opApply to iterate over a tree using foreach, see: https://tour.dlang.org/tour/en/gems/opdispatch-opapply