Am 28.09.2014 12:15, schrieb Marco Leise:
Am Thu, 25 Sep 2014 01:27:13 -0700
schrieb Walter Bright <newshou...@digitalmars.com>:
On 9/25/2014 12:10 AM, Manu via Digitalmars-d wrote:
> I think Microsoft's C++/CLI tried that mixed pointer approach, and it was a
disaster. I don't have personal knowledge of this.
C++ doesn't have any notion of borrowing. Scope can (will?) fix a whole lot of
existing problems, and also allow RC -> raw pointers work nicely.
Consider that people complain a lot about annotations. See the other thread.
Adding the scope annotations everywhere is a LOT of annotations. Do you think
people will be happy with that? I don't.
I remember reading a paper about someone adding pointer annotations to Java. It
was a technical success, and a usability failure. People just couldn't be
bothered to add the annotations.
You brought up these comparisons with near/far pointer earlier.
(They stay as vague.) And now you also argue against borrowing.
Please reconsider, since pointers do differ in their lifetimes.
We have that friction already and D is unable to plug the hole.
From the top of my head there are several bugs about escaping
stack pointers and RC is around the corner.
The extent of what borrowing solves is really yaw dropping
when you read the list of use cases and I will surely add
scope to every function argument that it applies to (and
already do that), because it makes it verifiable safe to call
with any pointer type, be it ARC, GC or stack. I consider that
more important than const or pure.
And why do you bring up Java? Does Java have any pointer types
other than GC? Is it a low level systems programming language?
No! So those annotations probably weren't an enabling feature
like "scope", right?
Depends on how you look at it.
Those type of annotations are used in meta-circular implementations of
Java. In those cases Java is a low level systems programming language.
Case in point,
Jikes, http://jikesrvm.org/
Annotations examples,
http://jikesrvm.sourceforge.net/apidocs/latest/org/vmmagic/pragma/package-summary.html
Oracle's Hotspot replacement Graal and Substrate VM AOT compiler,
http://lafo.ssw.uni-linz.ac.at/papers/2014_CGO_OneVMToRuleThemAll.pdf
--
PAulo
