https://issues.dlang.org/show_bug.cgi?id=13041
--- Comment #4 from Steven Schveighoffer <[email protected]> --- It certainly is possible. Note there is current work to update Transposed to use transverse to allow indexing https://github.com/dlang/phobos/pull/5805. I think we can go further building upon transverse, and its related option on how to treat the data. But it would be a strange relationship between transposed and its subranges. If the subranges were indexable, then Transposed can be a forward range, otherwise it can't. Seems unintuitive, and not sure it's worth all the effort. In other cases as well (if, for instance, the RangeOfRanges stores everything by value), then save could also be implemented. We may have a hard time detecting this because the relationship between Transposed and whether it's valid to make a copy is confusing and not well-established. --
