On Thu, 1 Dec 2022 at 05:03, Anony Mous <fyng...@gmail.com> wrote:
>
> Barry wrote:
>
> > The ways scoping works in python is very hard to change as you are asking
> > for i think was a major reason to reject.
>
> Perhaps it isn't all that difficult;
>
> For instance, a "local:" declaration could be treated as if it were "def
> function()" with an immediately succeeding call as far as the interpreter is
> concerned. That buys the scoping for (nearly) free.
>
> We write...
>
> local:
> for MyVal in range(0,10)
> pass
>
> ...interpreter codes that, out of sight, as:
>
> def ghost_func_0000001():
> for MyVal in range(0,10)
> pass
> ghost_func_0000001()
>
> Might take a bit of fiddling to make sure return and yield were appropriate
> [requiring an actual enclosing def function():], but other than that, it's
> basically the same idea -- provides scoping, making it easier for us to code,
> debug, and document, while significantly decreasing the likelihood of
> variable collisions.
>
def local(f): return f()
@local
def _():
for MyVal in range(0, 10):
pass
Not sure what you mean about "mak[ing] sure return and yield were
appropriate" though. Inside such a local block, are you expecting
yield and return to apply to the outer function? If so, it would most
definitely NOT be free for the interpreter to wrap it in a function,
as this would require some completely new functionality.
For a much, MUCH easier way to give semantics to this, here's a
concept that I put together for re-scoping "except Exception as e:" a
while back: the technical scoping rules remain exactly the same, but
the variable name is mangled. This would be similar to how mangled
names work in classes, and wouldn't require that the mangled names be
legal Python identifiers. For instance, this hypothetical code:
def foo():
e = 2.718281828
try: ...
except local Exception as e: ...
try: ...
except local Exception as e: ...
could be compiled to have local variables named "e", ".e.0", and
".e.1". As long as this occurs only at function scope, this has no
impact on the normal running of the code other than the locals()
dictionary (which would include all three variants, under those keys).
However, I don't think this is a good idea. It would work, kinda, but
it wouldn't be easy to describe, and that's usually a bad sign.
Without variable declarations, it's not usually worth having
infinitely nested scopes.
ChrisA
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