makeObserver in a loop / why does it use static struct?

[Robert-M-Muench]

makeObserver uses a static struct AnonymouseObserver{...}which, from my understanding, means that there is only one instance of this struct per thread. Hence, when I do this:

foreach(thing; myThings){
 myMasterThing.subscribe(
  makeObserver(
   (float f) {thing.myFunc(f);},
   (Exception) {}
  )
 );
}

I get a lof of observers, but they all point to the same function of the last thing in the loop.

But I would like to have an observer per thing. How to do this?

[Robert-M-Muench]

The solution seems to be to change it to:

foreach(thing; myThings){
 myMasterThing.subscribe(&thing.myFunc);
}

and have

myMasterThing.subscribe(void delegate() doPut){
 doSubscribe(myMasterThingStream, makeObserver(doPut, (Exception) {}));
}

[r4j4h]

Hi there, a little late but I think your initial approach might still be feasible.

I ran into this myself recently thankfully and here is a workaround I found. It ends up this is sort of a compiler bug! https://issues.dlang.org/show_bug.cgi?id=2043#c8 and https://issues.dlang.org/show_bug.cgi?id=2043#c10 clarify a way to "trick" the system into giving you a delegate per-iteration, and you can follow that thread for more info - it's all in the same bug thread.

(edit) sorry I might have jumped the gun on responding when I saw the foreach and that you were getiing the last thing in the loop because I didn't pay attention to the use of static. This may not work there. 😬