Python + Borland - msvcrt = grr.

[Steve Holden]

"Tim Peters" <tim.one at home.com> wrote in message
news:mailman.988070435.14712.python-list at python.org...
> [Paolo Invernizzi]
> > I think that use before assignment is one thing, and assignment that is
> > never used is another...
> > But it seems to me that the Borland warning is right, as is an
> > expression of inefficient code...
>
> Hardly:  if the compiler is smart enough to detect that an assignment is
> dead, it's also smart enough to refrain from generating any code for it.
> That makes it a nuisance complaint.
>
Personally I wouldn't object to a warning that says "take this source code
out, dummy, because I won't eb generating code for it anyhow". Allows me to
improve the maintainability of my code, and avoids other readers spending
time wondering why a brainfart is there.

But I agree it's a real pain in large projects when the initialisation is
there for reason (3) below...

Wouldn't even mind it *not* generating the code when it issued the warning
(as long as it is provably correct in doing so).

> > The "use before assignment" complain of other compilers is
> > justified? So why dont follow the more efficient way of coding?
>
> A) Under any decently optimizing compiler, it's not more efficient.
>
> B) To shut up bogus use-before-def warnings from dumber compilers (and
>    we *never* want to disable use-before-def warnings).
>
These would be the compilers that *do* generate code for the redundant
assignment?

> C) Because sometimes code is very complex, and under *modification*
>    it's very easy to miss a new path in the code in which a local
>    vrbl is suddenly not defined before use.  This isn't a nuisance
>    in C, it's a disaster.  Initializing vrbls in complex C code is
>    basic defensive coding practice.
>
Cannot disagree.

> > I dont work with a lot of compiler, but me too I'm a Borland
> > fan <wink>.
>
> Never used it, but sounds fine to me.  Surely they have options to shut up
> nuisance complaints, though?  You can do whatever you like in *your* code,
> but in the *Python* code base we try not to push compilers to their
limits,
> let alone readers' brains beyond them <wink>.
>
> half-successful-anyway-ly y'rs  - tim
>
wondering-which-half-some-days-ly y'rs  - steve