does python have useless destructors?
dkturner at telkomsa.net
Thu Jun 17 16:07:21 CEST 2004
Peter Hansen <peter at engcorp.com> wrote in message news:<htudnXIw-_HkalPdRVn-gQ at powergate.ca>...
> David Turner wrote:
> > I mean that it's very much easier for me to write provably correct
> > code in C++. Trying to do the same in Python is an uphill struggle.
> Interesting... when was the last time you proved that your C++
> program was correct? Honestly. I've *never* seen anyone prove
> a program was correct, especially not C++, though I know that
Very rarely do I do whole-program analysis. I don't know anyone who
does that either. What I'm talking about are small chunks of code
with critical behaviour. The mutex example I gave is a case in point.
I can prove, under a reasonable set of assumptions, that there is no
use-case that will lead to incorrect behaviour. This is far more
difficult in Python as I have to do the proof each time I use the
object. This is why formal proofs are rare in the industry - they
just become too complicated.
> some folks do seem to want to do that, and they apparently
> actually do in some environments. I'm just surprised to find
> anyone here who actually writes the kind of code that must have
> formal proofs done for it before it can be used...
I don't have a gun to my head. But I do have direct financial
liability, which is just as good :-).
> Also interesting. Have you actually tried using Python for big
> systems with multiple programmers, and encountered serious problems?
Admittedly I have not. I mostly use it to glue things together, in
which area it excels.
> I have just recently left a company where we had at least twenty
> man-years invested in one large Python system, with as many as about
> six Python programmers working on it simultaneously. I can say
> uncategorically that the software is the most stable and robust that
> I've ever been involved in writing. Any C, C++, Delphi, or Java
> system in which I was previously involved was definitely less robust.
Interesting. I must say I'm a little envious :-).
> Since it's therefore obviously not a property of these languages
> that they are robust or not, it must be something more to do with
> the programmers, or the process, or something. I guess... ;-)
I don't see how the "obviously" bit follows. But I will say that I
know of almost no software makers out there that use C++ "properly".
99% of the code I've seen out there is "C with classes". I'd be happy
to discuss my views on what constitutes "proper" use of C++, but this
is not the forum for that :-).
> Sounds like two worlds here. We didn't need contracts or enforcement
> of this kind. Our developers were working test-first, with as wide
> coverage of unit tests as possible, so we already knew the code was
> going to be pretty good without getting into B&D like that. I can
> see you have not adopted the XP mentality and test-driven development,
> so our thoughts on this whole matter are inevitably going to be
I agree. Not much point in getting into an argument over that :-).
But the two approaches are not necessarily mutually exclusive:- some
bits of the program (read libraries) require careful thought and
design before a line of code is written; other bits (read purposive
code) do better in a test-driven environment.
My "other bits" tend to be a tiny fraction of the whole, so please
excuse me if I exhibit some bias towards top-down development ;-).
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