On 25/07/2016 10:13 AM, bitwise wrote:
Any thoughts on an @gc attribute for bypassing @nogc?
As much as I like to cringe at the GC when I'm using C#, I can't ignore
my level of productivity, as it compares to projects I've done in C++.
If I had to write a butter-smooth AAA game, it may be a problem, but at
present, my thoughts on a few small jitters here and there are....who
cares?
As long as GC usage is kept to a minimum, things will usually work ok fine.
For example, in a game, I may create a script with an "update" method
that gets called each frame. I wouldn't want people(or myself)
accidentally allocating memory here, possible 30-60 times per second, so
I would make that function @nogc. But, there *will* be cases where I
actually want to allocate something, for example, to spawn a piece of cake.
Example:
class Cake{}
class MyScript {
SysTime when;
this() { when = Clock.currTime + 5.seconds; }
void update() @nogc {
// ...
if(Clock.currTime >= when) {
@gc {
Cake c = new Cake();
}
}
}
}
void main(string[] args) {
MyScript script = new MyScript();
foreach(i; 0..10) {
script.update();
Thread.sleep(1.seconds);
}
}
There is the following, which is clever. But if it came down to having
to do this to bypass @nogc, I simply wouldn't use @nogc.
https://p0nce.github.io/d-idioms/#Bypassing-@nogc
When you have to do it thousands of times throughout your codebase, then
yes, it's that bad.
Bit
I've been saying for a very long time we need @assumenogc attribute like
we have @trusted for @safe.
I have not been taken very seriously about this...
Although I see no reason to allow GC in @assumenogc as long as it does
not trigger scan/collect phase of it. After all, why don't we have a
hint on allocation if we do or do not want it to trigger a scan?
Or even better, a thread local stack to specify this!
