On Thursday, 13 November 2014 at 10:24:44 UTC, Marc Schütz wrote:
On Thursday, 13 November 2014 at 10:00:10 UTC, Ola Fosheim
Grøstad wrote:
It is better solved using static analysis
You mean without additional hints by the programmer? That's not
going to happen, realistically, for many reasons, separate
compilation being one of them.
I think it can happen. D needs a new intermediate layer where you
can do global flow analysis.
compile src -> ast -> partial evaluation -> high level IR -> disk
instantiate high level IR -> intermediate IR -> disk
global analysis over intermediate IR
intermediate IR -> LLVM -> asm
Huh? That's exactly what _borrowing_ does. Ref-counting OTOH
adds yet another reference type and thereby makes the situation
worse.
I don't like explicit ref counting, but it is sometimes useful
and I think Rust-style ownership is pretty close to unique_ptr
which is ref-counting with a max count of 1… You can also view GC
as being implicitly ref counted too (it is "counted" during
collection).
What does "shared" tell the compiler?
I guess you mean "scope"?
:)
It tells it "retain no references after completion of this
function". Like with "pure", it should be opposite. You should
tell the compiler "I transfer ownership of this parameter".
Then have a generic concept "owned" for parameters that is
resolved using templates.
That's what deadalnix's proposal does. Though I don't quite see
what templates have to do with it.
My understanding of Deadalnix' proposal is that "owned" objects
can only reference other "owned" objects. I think region
allocators do better if you start constraining relations by
ownership.
For a new language built from scratch, this might make sense. D
is already existing, and needs to work with what it has.
D need to appropriate what C++ has and do it better. Basically it
means integrating GC pointers with unique_ptr and shared_ptr.
If D is going to be stuck on what it has and "fix" it with addig
crutches it will go nowhere, and C++ will start to look like a
better option…
