Am 08.05.2014 15:57, schrieb monarch_dodra:
On Thursday, 8 May 2014 at 12:48:17 UTC, Sönke Ludwig wrote:
Am 08.05.2014 13:05, schrieb monarch_dodra:
Not necessarily: As soon as indirections come into play, you are
basically screwed, since const is "turtles all the way down".
So for example, the conversion from "const RefCounted!T" to
"RefCounted!(const T)" is simply not possible, because it strips the
const-ness of the ref count.
What we would *really* need here is NOT:
"const RefCounted!T" => "RefCounted!(const T)"
But rather
"RefCounted!T" => "RefCounted!(const T)"
The idea is to cut out the "head const" directly. This also applies to
most ranges too BTW.
We'd be much better of if we never used `const MyRange!T` to begin with,
but simply had a conversion from `MyRange!T` to `MyRange!(const T)`,
which references the same data.
In fact, I'm wondering if this might not be a more interesting direction
to explore.
The reference count _must_ be handled separate from the payload's
const-ness, or a const(RefCount!T) would be completely dysfunctional.
Right, which is my point: "const(RefCount!T)" *is* dysfunctional, which
is why you'd want to skip it out entirely in the first place.This holds
true for types implemented with RefCount, such as Array and Array.Range.
Okay, I didn't know that. For various reasons (mostly weak ref support)
I'm using my own RefCount template, which casts away const-ness of the
reference counter internally.
