Automatic debugging of copy by reference errors?

[Russ]

greg wrote:

> You need to stop using the term "copy by reference",
> because it's meaningless. Just remember that assignment

I agree that "copy by reference" is a bad choice of words. I meant pass
by reference and assign by reference. But the effect is to make a
virtual copy, so although the phrase is perhaps misleading, it is not
"meaningless."

<cut>

> Again, this is something you'll find easier when
> you've had more experience with Python. Generally,
> you only need to copy something when you want an
> independent object that you can manipulate without
> affecting anything else, although that probably
> doesn't sound very helpful.

Yes, I realize that, but deciding *when* you need a copy is the hard
part.