Generic and fundamental language design issue

[Tommi]

On Sunday, 4 November 2012 at 18:14:36 UTC, Dmitry Olshansky 
wrote:
> In fact placing big object on stack just because it fits could 
> introduce stack overflow few hundred calls later.

But that's kind of my point also. For example:

void func(T)(int n)
{
     if (n <= 0)
         return;

     auto t = <create variable t of type T>
     ...
     func!(T)(n - 1);
}

If func is called with a runtime argument n, then the programmer 
cannot determine the most sensible way to allocate for variable 
t. What I'd like to happen is that, at runtime, every time a 
variable t is created, the program would determine the best way 
to allocate the memory for it, based on the available stack size 
(prefer stack if there's room there).

On Sunday, 4 November 2012 at 18:14:36 UTC, Dmitry Olshansky 
wrote:
> In general compiler can't know beforehand how big stack space 
> you'll need and thusly the portion of it to use safely.

Yeah, I just realized it can't be done at compile-time. Making 
the decision between stack or heap allocation should happen at 
run-time.