On Friday, 27 November 2015 at 09:20:23 UTC, Jonathan M Davis
wrote:
Obviously, Andrei will have to answer to know what he meant,
but with regards to ranges, I would consider a reference type
to be one where in
auto copy = range;
doing anything to copy or range does the exact same thing to
the other, because they refer to the exact same state.
Something like save is required to get a separate range where
popping elements from one will not affect the other.
Unfortunately it's a bit more complicated than that, because it's
readily possible to have ranges where
auto copy = range;
... will copy _some_ of the internals by value, and some by
reference -- e.g. a range whose private data includes some
integer values and a dynamic array.
That's not necessarily a problem if the reference-type data does
not influence the range's behaviour (e.g. you're doing forward
iteration over a container accessed by ref), but it's readily
possible to imagine a range design where
auto copy = range;
copy.popFront();
... will affect range's state without updating it to the _same_
state as copy.
