* Steven D'Aprano:
On Thu, 19 Nov 2009 21:37:17 +0100, Alf P. Steinbach wrote:
The CPython 3.1.1 language reference ยง4.1 says
"Each command typed interactively is a block."
It also says
"If a name is bound in a block, it is a local variable of that block,
unless
declared as nonlocal"
Even with a non-literal try-for-best-meaning reading I can't get this to
mesh with the actual behavior of the interpreter, e.g.
>>> for x in "poi":
... fandango = 666
...
>>> fandango
666
>>> _
My current understanding is (A) that the interpreter is correct in this
respect (for one would harldly want the effects of statements to be
fundamentally different in interpreted mode, except the presentation of
expression results), and (B), but here I'm less sure, that the
documentation is incorrect.
Why do you say that? I don't see what it is in the command you typed that
leads you to think the documentation is incorrect.
The first command you type is:
for x in "poi":
fandango = 666
which binds two names, x and fandango. Since you are not typing them in a
function or class definition, locals() is globals() and the two local
names you create happen to also be globals.
Thanks, that may be it.
In most other languages I'm familiar with, if a name is local then it isn't
global (and vice versa), and I had that as an underlying assumption since it
doesn't appear to be mentioned in the documentation.
However, I find a language reference statement that alludes to this: "(The
variables of the module code block are local and global.)"
Hm...
The next two commands you type:
fandango
_
don't bind anything, so aren't relevant.
Well it showed that 'fandango' had been defined as a global. :-)
If it helps:
for x in "poi":
... fandango = 666
...
locals() is globals()
True
fandango
666
locals()['fandango']
666
import __main__
__main__.fandango
666
Yeah, helps.
I feel that there's still something lacking in my understanding though, like
how/where the "really actually just pure local not also global" is defined for
function definition, but it's now just a vague feeling of something missing, not
a feeling of direct contradiction as I had when I believed local != global.
Cheers, & thanks,
- Alf
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