On Saturday, 28 November 2015 at 13:39:35 UTC, Andrei
Alexandrescu wrote:
On 11/28/15 1:59 AM, bitwise wrote:
Classes/real-ref-types dont act as you're describing, so why
should
these fake struct wrapper ref things act this way? This will
likely
achieve the exact opposite of what you're aiming for, by making
something that's supposed to act like a reference type have
different
behaviour from D's built in ref types.
So what would work for you? -- Andrei
Sorry if that response seemed a tad flippant, but I have to be
honest...I am completely against this design...to put it mildly.
I have my own containers to use, but on top of the fact that I
would prefer something which is collaboratively maintained, I
don't want to be forced to deal with, or support these
"reference" containers, which will most likely happen if they get
added to Phobos.
I'm really not sure where to begin tearing this idea apart. The
principal I have a problem with is much more fundamental than
this one decision. In general, there is a lot in D that is very
hackish.
I understand that you don't want eager copying of containers, but
when I way predictability, simplicity, clarity, and flexibility
against that concern, there is no way I'm agreeing with you, when
you can simply wrap a proper container in a RefCounted(T) or
something. A class is a reference type, and a struct is a value
type. If a user sees a struct, they should expect a value type
which will copy on assign, and if they see a class, they should
expect a reference. In D, the differentiation between value and
reference types is clearly specified, and D users _should_ be,
and should be expected to be, aware of it.
If you really want reference containers, they should be
implemented either as value-type structs, or classes that can
work with RefCounted(T). Baking the reference count directly into
the container is limiting, and buys nothing. I really don't see a
problem with GC'ed classes if you really want reference types.
It's going to be forever, if ever before you can actually turn
off the GC when using Phobos. At least, if it's a class, you can
use Scoped(T), or RefCounted(T) on it...assuming RefCounted(T) is
fixed up to work with classes at some point, which seems like a
better path then baking ref counting into a container
implementation.
I'm feeling a bit repetitive at this point, and wondering if I
should have responded to this at all, and I'm sure you know
exactly what I'm talking about, and that it's a matter of choice
at this point, but there you have it.
Bit
