On Thu, May 27, 2021 at 7:20 PM Ronald Oussoren via Python-ideas
<python-ideas@python.org> wrote:
> On 27 May 2021, at 09:56, Shreyan Avigyan <pythonshreya...@gmail.com> wrote:
>
> > Static should behave much like Python's for loop variables.
I have no idea what this means.
>
> For this particular question/proposal: “static” variables in functions in C
> like languages are basically hidden global variables, and global variables
> are generally a bad idea.
>
Hmm, I'd distinguish a couple of things here. Global constants are
most certainly not a problem, and objects that last the entire run of
the program are not a problem either. The usual problem with "global
variables" is that they become hidden state, action-at-a-distance. You
can change the global in one function and it notably affects some
other function. Part of the point of statics is that they are *not*
global; they might live for the entire run of the program, but they
can't be changed by any other function, so there's no AaaD that will
mess with your expectations.
> In Python you can get the same result with a global variable and the use of
> the “global” keyword in a function (or cooperating set of functions) when you
> want to update the global variable from that function.
>
That's globals, with all the risks thereof.
> Closures or instances of classes with an ``__call__`` method can be used as
> well and can hide state (with the “consulting adults” caveat, the state is
> hidden, not inaccessible).
>
This would be the easiest way to manage it. But both of them provide a
way to have multiple independent, yet equivalent, states. If that's
what you want, great! But it can also be an unnecessary level of
confusion ("why would I ever make a second one of these? Why is there
a factory function for something that I'll only ever need one of?"),
where static variables wouldn't do that.
There is one namespace that would very aptly handle this kind of
thing: the function object itself.
>>> def count():
... count.cur += 1
... return count.cur
...
>>> count.cur = 0
>>> count()
1
>>> count()
2
>>> count()
3
>>> count()
4
As long as you can reference your own function reliably, this will
work. There may be room for a keyword like this_function, but for the
most part, it's not necessary, and you can happily work with the
function by its name. It's a little clunkier than being able to say
"static cur = 0;" to initialize it (the initializer has to go *after*
the function, which feels backwards), but the functionality is all
there.
ChrisA
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