Memory management dilemma

[Jeff Parsons]

Hi

Straight to the point: I'm having trouble finding a clean way to make 
sure memory that's no longer required by my game is freed.

I need to manage memory explicitly since it seems to be impossible to 
guarantee long-term smooth operation when using only garbage collection. 
I don't see introducing artificial pauses into gameplay during which 
garbage is collected, or allowing the game to bloat horribly over time 
as solutions.

Example of my problem:

In C++, I could pass my spatial Vector/Vector3D/whatever class, or 
Matrix class by value. I could chuck it around in expressions happily, 
etc. In D, I have a few concerns:

[*] I can see a LOT of manual "delete whatever" popping up if I'm 
dealing with expressions that involve a lot of vector or matrix math. Is 
there a way to avoid this (having locally created objects automatically 
destroyed when they go out of scope)?
[*] If I explicitly copy my objects when passing them to functions and 
explicitly destroy them at the end of the called function, won't this be 
allocating a lot on the heap, and therefore be slow?
[*] How are temporaries handled if there's no garbage collector active? 
For example, if part of an expression calls a.getB() which returns a 
reference to one of a's members called b, does D know not to mess with 
this reference when cleaning up temporaries? What if getB() assigned a 
new object to b, but returned the original reference. How would it 
behave then - would it know it's not safe to destroy it?

Is there a nice neat way to handle this in D or should I expect a lot of 
pain when not using the garbage collector? And if I do go down this 
path, how can I tell if I -am- leaking memory?

Any and all comments and/or suggestions are appreciated.

Thanks :)

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Footer for the bored:
I don't think I've posted here, so to quickly introduce myself, my name 
is Jeff Parsons and I'm an undergraduate Computer Science student who 
really doesn't want to go crawling back to C++ quite so soon. ;)