Shout out to D at cppcon, when talkign about ranges.

[Kagamin via Digitalmars-d]

On Thursday, 8 October 2015 at 22:57:01 UTC, Timon Gehr wrote:
> Isn't this the same as my suggestion?
> http://forum.dlang.org/post/mv3q34$bbg$1@digitalmars.com
>
> If not, what is the difference?

Your range is undoable. The difference I see is that you use full 
(should be frontFull) and pushFront to go left, I use normal 
backward input range, empty and popBack - existing primitives. 
Also pushFront may suggest you're adding new items at the front, 
maybe your methods should be frontUndoEmpty and undoPopFront?