The quest to understand refcnt

"dev42" wrote:
FWIW, I'm learning *more* and have just discovered that I can step thru code in the debugger... so I *should* be able to insert multiple STOP's and watch the change of the refcnt, yes? !!!

Probably. But don't obsess about reference counts, just have faith that it works "like magic" and in most cases you have nothing to worry about, the system takes care of objects lifetime and disposal. Avoid using globals (GetGlobalAA()) when you can pass something as argument and you should be fine, since leaving out of nested functions will be cleaning behind.

For edu-tainment's sake, i made here an artificial example to demonstrate how one "memory leak" happens:

function Stack(n):
    dim stk[n]
    return {
        stk: stk,
        ptr: 0,
        push: function(x): m.stk[m.ptr] = x: m.ptr = m.ptr + 1: end function,
        pull: function(): m.ptr = m.ptr - 1: return m.stk[m.ptr]: end function
    }
end function
...
' the following is in main()
s = stack(100)
for i = 1 to 10: s.push( createObject("roScreen") 😞 end for
for i = 1 to 10: screen = s.pull(): end for
screen = invalid
' at this point all roScreens should be closed, right? wrong!
...

So i got a factory function Stack(n) that constructs a stack with N elements and 2 methods, `push` and `pull` that respectively add and remove elements. Then i shove 10 roScreens on that stack, then i take them back and even invalidate the last one. And yet, they are not all gone. How come? - figuring that out will be a good exercise.