Re: Anonymous nogc class
On Friday, 8 September 2017 at 16:10:55 UTC, Biotronic wrote: On Friday, 8 September 2017 at 12:32:35 UTC, Jiyan wrote: [...] It's scoped!T's destructor. If you decide to use that workaround, you should probably copy scoped!T from std.typecons and have your own version. It's not safe in all cases, and the next standard library update might break it. [...] In your case, scoped!T is can be safely called from @nogc code, and thus could be marked @nogc. However, when a class C has a destructor that allocates, scoped!C could not be @nogc. So in order to be safe in all cases, it can't be @nogc in the general case. -- Biotronic Thank you very much :)
Re: Anonymous nogc class
On Friday, 8 September 2017 at 12:32:35 UTC, Jiyan wrote: On Friday, 8 September 2017 at 06:37:54 UTC, Biotronic wrote: On Thursday, 7 September 2017 at 23:40:11 UTC, Jiyan wrote: [...] Sadly, even std.typecons.scoped isn't currently @nogc: https://issues.dlang.org/show_bug.cgi?id=13972 https://issues.dlang.org/show_bug.cgi?id=17592 [...] First thanks :) i understand the part with scopedAnon, but can you explain what the ~this is referring to? Is it the Modul destructor? It's scoped!T's destructor. If you decide to use that workaround, you should probably copy scoped!T from std.typecons and have your own version. It's not safe in all cases, and the next standard library update might break it. And in general is it just that scoped is just not marked @nogc or is it that it would really need to use the gc? In your case, scoped!T is can be safely called from @nogc code, and thus could be marked @nogc. However, when a class C has a destructor that allocates, scoped!C could not be @nogc. So in order to be safe in all cases, it can't be @nogc in the general case. -- Biotronic
Re: Anonymous nogc class
On Friday, 8 September 2017 at 06:37:54 UTC, Biotronic wrote: On Thursday, 7 September 2017 at 23:40:11 UTC, Jiyan wrote: [...] Sadly, even std.typecons.scoped isn't currently @nogc: https://issues.dlang.org/show_bug.cgi?id=13972 https://issues.dlang.org/show_bug.cgi?id=17592 [...] First thanks :) i understand the part with scopedAnon, but can you explain what the ~this is referring to? Is it the Modul destructor? And in general is it just that scoped is just not marked @nogc or is it that it would really need to use the gc?
Re: Anonymous nogc class
On Thursday, 7 September 2017 at 23:40:11 UTC, Jiyan wrote:
Hey,
wanted to know whether it is possible to make anonymous nogc
classes:
interface I
{
public void ap();
}
void exec(I i)
{
i.ap;
}
// now execute, but with something like `scope`
exec( new class I
{
int tr = 43;
override void ap(){tr.writeln;}
});
Thanks :)
Sadly, even std.typecons.scoped isn't currently @nogc:
https://issues.dlang.org/show_bug.cgi?id=13972
https://issues.dlang.org/show_bug.cgi?id=17592
This can be worked around by casting scoped's destructor to be
@nogc, but that's a heavy-handed approach that ruins type safety,
and is the wrong solution in non-@nogc situations. Should you
want to, this is what it should look like:
~this()
{
(cast(void delegate(T) @nogc)((T t){
// `destroy` will also write .init but we have no
functions in druntime
// for deterministic finalization and memory
releasing for now.
.destroy(t);
}))(Scoped_payload);
}
If and when this issue is resolved, this should work:
interface I {
public void ap();
}
void exec(I i) {
i.ap;
}
auto scopedAnon(T)(lazy T dummy) if (is(T == class)) {
import std.typecons;
return scoped!T();
}
unittest {
auto i = scopedAnon(new class I {
int tr = 43;
override void ap() {
import std.stdio;
tr.writeln;
}
});
exec(i);
}
--
Biotronic
Anonymous nogc class
Hey,
wanted to know whether it is possible to make anonymous nogc
classes:
interface I
{
public void ap();
}
void exec(I i)
{
i.ap;
}
// now execute, but with something like `scope`
exec( new class I
{
int tr = 43;
override void ap(){tr.writeln;}
});
Thanks :)
