Transience of .front in input vs. forward ranges

[deadalnix]

Le 04/11/2012 03:26, Jonathan M Davis a écrit :
> 3. Make it so that ranges which can be transient are non-transient by default
> but provide a function to get at a transient version for speed (which was the
> fastRange proposal in this thread). The main problem here is that when the
> fast range gets wrapped, it's transient, and so anything using the wrapped
> range will be forced to use the transient version rather than using the non-
> transient version and only using the transient version when it's asked for.
> So, I don't think that this is particularly viable.
>

Can you elaborate on that. I definitively don't see a problem that big here.