The problem is not only about freeing memory but releasing the resources to the
pool of resources (OS, database, etc.).
Let say I have a bit of code
proc getIter(p: Params): iterator: int =
iterator iterWithResources: int {.closure.} =
...
result = iterWithResources
...
let iter = getIter(someParams)
for i in iter():
...
Run
If I understand correctly the [Nim Destructors and Move
Semantics](https://nim-lang.org/docs/destructors.html) documentation, I would
need to write a destructor proc for the type of the variable `iter`. What is
its type?
The compiler error message explicitly shows that `=destroy` proc only apply to
`object` types. So how do you define a destructor (or a resource collection
proc) for an iterator?
And is there a way, in that destructor, to know if the iterator completed
successfully or if it is still alive? If the iterator completed, normally the
resources have been released: there is no need to do something in the
destructor. But if it did not complete and is still waiting for the next call,
then the programmer has to free the resources.
