On Monday, 7 August 2017 at 10:50:21 UTC, Mike wrote:
On Sunday, 6 August 2017 at 15:47:43 UTC, Moritz Maxeiner wrote:
If you use this option, do be aware that this feature has been
scheduled for future deprecation [1].
It's likely going to continue working for quite a while
(years), though.
[1]
https://dlang.org/deprecate.html#scope%20for%20allocating%20classes%20on%20the%20stack
FYI: http://forum.dlang.org/post/np1fll$ast$1...@digitalmars.com
"Yes, it will have to be updated - but I didn't want to adjust
it before DIP1000 spec is finalized. Rationale that was driving
deprecation of scope storage class is becoming obsolete with
DIP1000 implemented but not before."
Thanks, I wasn't aware of this. I tried fooling around scope
classes and DIP1000 for a bit and was surprised that this is
allowed:
---
import core.stdc.stdio : printf;
import std.algorithm : move;
class A
{
int i;
this() @safe
{
i = 0;
}
}
void inc(scope A a) @safe
{
a.i += 1;
}
void print(scope A a) @trusted
{
printf("A@%x: %d\n", cast(void*) a, a.i);
}
auto makeA() @safe
{
scope a = new A();
a.print();
return move(a);
}
void main() @safe
{
auto a = makeA();
foreach (i; 0..10) {
a.print();
a.inc();
}
}
---
You can still create a (scope) class on the stack, escape a
reference to it using `move` and use it afterwards, all within
the rules of @safe, so I'm not convinced that the reason for
deprecating scoped classes is gone yet.
Compare this to `scoped`, which behaves as expected (since it
wraps the reference type object in a value type):
---
import std.typecons : scoped;
auto makeA() @trusted
{
auto a = scoped!A();
a.print();
return move(a);
}
void main() @trusted
{
auto a = makeA();
foreach (i; 0..10) {
a.print();
a.inc();
}
}
---
